Glossary – H


Haarlem: a city in north Holland, near Amsterdam.

habeas corpus: a legal recourse against unlawful imprisonment.

Haber process: a process for synthesizing ammonia, involving the nitrogen fixation reaction via hydrogen gas and nitrogen gas, catalyzed by enriched iron or ruthenium; named after Fritz Haber, its inventor.

habitable zone (aka circumstellar habitable zone, Goldilocks zone, comfort zone): a range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure. The radiant energy a planet receives from the star it orbits is a critical factor.

habitat: the environment in which a species population lives.

Hadean (4.55–3.9 bya): the 1st geologic eon, originally thought to be before life originated on Earth (but life started 4.1 BYA).

Hadley cell: an atmospheric circulation belt between the equator and latitude 30° (the Horse Latitudes). The Hadley cell is named after George Hadley, who was intrigued by the trade winds having a pronounced westerly flow, rather than blowing straight north. In generally explaining the gyre of the trade winds in 1735, Hadley’s explanation accounted for the Coriolis effect. See Ferrel cell and Polar cell.

hadron: a composite subatomic particle made of a variety of quarks. Matter is comprised of baryons: hadrons composed of 3 quarks.

Hagenberg (mass extinction event 358 mya): the last of 8 to 10 extinction pulses during the Devonian. The Hagenberg extinction event, on the boundary with the Carboniferous, affected both marine and terrestrial biomes.

hairstreak: a small butterfly with striped markings under its wings, in the Lycaenidae family.

hairworm (aka nematomorpha, horsehair worm, Gordian worm): a phylum of water-loving parasitoid worms, superficially similar to nematodes.

half-life: the duration required for a material to decay to half of its initial value. The probabilistic term is commonly used in nuclear physics to state the radioactive decay rate of atoms. Medical sciences use half-life to refer to the biological breakdown of chemical substances in the body.

halfbeak (aka Buffon’s river garfish, Zenarchopterus buffonis): a smallish fish found near the surface of rivers, estuaries, and coastal waters ranging from southern China to northern hallucination: a vivid, convincing sensation in absence of external stimuli while awake. Contrast dream.

Hallucigenia: a genus of small Cambrian tubular animals, 0.5–3.5 cm long.

hallucination: a vivid, convincing sensation in absence of external stimuli while awake. Compare dream.

hallucinogen: a psychoactive chemical agent, classified into 3 broad categories: psychedelics, dissociatives, and deliriants.

halogen: a group of chemically related elements, so named because they all produce sodium salts with similar properties (hal being Greek for salt, and gen for generate). The 4 natural halogen elements are fluorine (F), chlorine (Cl), bromine (Br) and iodine (I). Astatine (At) is a halogen that exists as a short-lived radioactive isotope, as is the artificially conceived element 117 (ununseptium (Uus)).

haloarchaean: a salt-loving archaean.

halophile: an organism that lives in a salty habitat.

halophyte: a plant that grows in saltwater. Salt marsh grasses and mangrove trees are halophytes.

Halszkaraptor: a unique genus of feathered, largely aquatic, maniraptoran therapod with duck-like legs for walking and forelimbs well-adapted for swimming. Only 1 species – H. escuilliei – is known.

hamadryas baboon (Papio hamadryas): the northernmost of baboons, native to the Horn of Africa and the southwestern tip of the Arabian Peninsula. Hamadryas have a pronounced sexual dimorphism. Males are often twice the size of females. This coincides with a strict patriarchal society. The hamadryas baboon was sacred to the ancient Egyptians.

Hamilton’s principle: the principle that the dynamics of a physical system are determined via variation in the Lagrangian function, which contains all information about the system and the forces acting upon the system. Originally formulated for classical mechanics by William Rowan Hamilton in 1833. Hamilton’s principle also applies to classical fields (e.g., electromagnetism, gravity), and is relevant to quantum mechanics, quantum field theory, and criticality theories.

Hamiltonian mechanics: a reformulation of classical mechanics used in characterizing quantum mechanical systems. The Hamiltonian refers to the total energy of a system. A Hamiltonian system is a dynamic system governed by Hamilton’s equations, which were derived by William Rowan Hamilton in 1833.

hammer-headed bat (aka big-lipped bat, Hypsignathus monstrosus): a megabat common in equatorial Africa.

hamster: a burrowing, crepuscular group of rodents of 6–7 genera and ~25 species. Hamsters eat primarily seeds, fruits, and vegetation, occasionally munching burrowing insects. Hamsters are larder hoarders, using their expandable cheek pouches to transport food to their burrows.

Hansa (aka Hanseatic League, Hanse): a defensive and commercial confederation of merchant guilds and market towns along the coast of northern Europe from the 13th–17th centuries.

haplodiploidy: a sex-determination system where the sex of offspring is determined by the number of sets of chromosomes received. Female eusocial (Hymenopteran) insects, such as bees, wasps, and ants, are diploid, but males are haploid because they develop from unfertilized, haploid egg cells.

haploid: a cell having 1 set of chromosomes. Compare diploid.

happiness: a mood of well-being. Compare bliss.

harbor seal (aka common seal): a seal found along Arctic and temperate marine coastlines in the Northern Hemisphere.

hard news: media coverage of current events. Contrast soft news.

hardware (computer): the physical devices associated with a computer. Contrast software.

Harley-Davidson (1901–): American motorcycle manufacturer.

harmony (music): a simultaneous combination of tones.

Harris’s hawk (aka bay-winged hawk, dusky hawk, Parabuteo unicinctus): a medium-large hawk found in the southwestern United States south to Chile, central Argentina, and Brazil. Harris’s hawk is notable for its pack hunting.

hartebeest (aka kongoni): an African antelope.

harvest mouse: a small rodent in the Micromys genus, native to Eurasia.

harvester ant: an ant that collects seeds and stores them in a communal granary. One Southeast Asian species – Euprenolepis procera – harvests mushrooms.

hate: intense negative emotional attachment to something.

haustorium: a hook used by parasitic fungi and plants to attach and draw nutrients from their chosen host. A haustorium may be shaped like a balloon or glove, or spiral-shaped.

Hawaiian bobtail squid (Euprymna scolopes): a bioluminescent squid, courtesy of the bacteria Vibrio fischeri. The Hawaiian bobtail squid is native to the central Pacific Ocean, living in shallow coastal waters.

Hawaiian Islands: an archipelago of 8 major volcanic islands in the North Pacific Ocean. The islands are the exposed peaks of an extensive undersea mountain range, formed over a volcanic hotspot.

hawk: a bird of prey, of various sizes and genera, in the Accipitridae family.

Hawking radiation: black-body radiation emitted by black holes, predicted by Stephen Hawking in 1974.

hawkmoth: a moderate- to large-sized moth in the Sphingidae family, with 1,450 species, found mostly in the tropics, but represented in many biomes. As moths, hawkmoths are distinguished for their rapid, sustained flying ability, adaptively equipped with narrow wings and streamlined abdomens.

Hawthorne effect (aka observer effect): a behavioral reaction to being observed.

Haymarket riot (4 May 1866): a riot in Chicago incited by police during a labor demonstration.

hazel grouse (aka hazel hen, Tetrastes bonasia): a relatively small (~37 cm), shy, terrestrial, sedentary grouse endemic to woodlands throughout northern Eurasia.

hd (holistic dimensionality): the totality of cosmic dimensions. hd refers to the universe having more than 4 dimensions (4d = 3 spatial dimensions and 1 time vector). hd = 4d + ed, where ed = extra (spatial) dimensions.

hearing: sound detection. Compare audition.

heat capacity (aka thermal capacity): the amount of heat needed to raise the temperature of a substance. See specific heat capacity.

heat engine: a machine that transforms a portion of the thermal energy entering it into mechanical power.

heath: a low evergreen shrub of over 700 species in the Erica genus; related to heather (Calluna); both genera are in the Ericaceae family.

Heaven: a common religious notion of a residence for souls departed from corporeal existence. Mythologies about Heaven are extensive. Some include a bifurcation, based upon divine judgment, that good souls ascend to Heaven, while bad souls descend to Hell, a place of eternal torment.

heavy water (deuterium oxide (D2O)): water with a higher hydrogen content (deuterium) than typical (light) water.

Hebrews: early Israelites, especially in pre-monarchic times, when they were still nomadic.

hectare: the standard metric unit of area; 1 hectare = 10 km2, 2.47 acres.

hectocotylus (plural: hectocotyli): a tentacle of male cephalopods that is specialized to store and transfer spermatophores to a female.

hedgehog: a spiny omnivorous mammal endemic to parts of Europe, Asia, and Africa, of 17 species in 5 genera.

hedonia: happiness from pleasure. Contrast eudaimonia.

hedonism: the school of thought that pleasure is the only intrinsic good. Ethical hedonism is the creed that people have the natural right to do everything in their power to get the greatest amount of pleasure possible.

hedge fund: an exclusive investment fund. Hedge funds are unregulated.

hegemony: influence exercised by one nation over others.

Heisenberg’s uncertainty principle: see uncertainty principle.

helicase: a class of enzymes that unpackage nucleic strands (DNA, RNA). Helicases are vital to all organisms.

heliocentrism: the theory that the Sun is the center of the solar system, around which planets orbit. Historically called the Copernican principle.

Helicobacter pylori: a bacterium that lives in the stomach. Over 50% of the world human population harbor H. pylori. The bacterium instigates gastritis or ulcers in less than 20% of those that carry it.

heliobacteria: phototrophic bacteria.

heliocentrism: the theory that the Sun is the center of the solar system around which planets orbit, including Earth.

Heliconia: a genus of 100– 200 flowering plant species, native to the tropical Americas and Pacific Ocean islands west to Indonesia.

heliosphere: a plasma bubble of charged particles in space blown by the solar wind.

helium (He): the element with atomic number 2; a colorless, odorless, tasteless, non-toxic, inert, monatomic gas. Helium is the 2nd lightest and 2nd most abundant element, behind hydrogen.

hellebore: an herbaceous or evergreen perennial of ~20 species in the Helleborus genus. Many species are poisonous.

Hellenistic period (323–31 BCE): a period in ancient Greek history between the death of Alexander the Great and the emergence of the Roman Empire, signified by the Battle of Actium.

helminth: a worm-like eukaryotic parasite.

helot: a Spartan slave. The Spartans were savage to their helots.

hematophagy: feeding on blood.

heme (aka haem): a deep red, iron-containing pigment (C34H32N4O4Fe) which readily oxidizes.

hemicellulose: a polysaccharide matrix in plant cell walls. In contrast to stiff cellulose, hemicellulose has little rigidity.

hemiepiphyte: a plant that spends part of its life as an epiphyte.

hemimetabolous: a type of metamorphosis in which physical development proceeds from egg to nymph to adult. Compare ametabolous, holometabolous.

hemiparasitism: a plant that is parasitic by inclination, but able to live on its own. Contrast obligate parasitism. Compare facultative parasitism.

hemipenis (plural: hemipenes): 1 of a pair of intromittent organs of male squamates. Hemipenis is a portmanteau of hemi (meaning half) and penis. Only 1 hemipenis is used at a time for sex. Males tend to alternate their hemipenes for successive copulations. Hemipenes are usually held within the body, inverted. They are everted for sex via erectile tissue. As hemipenes are inverted and everted, there is no closed sperm channel; instead, a seminal groove which seals closes as the erectile tissue expands. Hemipenis shape varies by species. Hemipenes often have spines or hooks to better anchor the male in the female.

hemlock (Conium maculatum): an herb native to Europe and the Mediterranean, notorious for producing the toxic alkaloid coniine.

hemlock: a genus (Tsuga) of pines.

hemlock (Conium maculatum): a poisonous plant in the parsley family, with purple-spotted stems, finely divided leaves, and umbels of small white flowers; a powerful sedative when used medicinally.

hemocoel: interconnected body cavity spaces between tissues through which blood freely flows, unconfined by blood vessels. Several invertebrate groups, including arthropods and mollusks, have hemocoel.

hemocoelic: having a blood vascular system.

hemocyanin: the copper-based protein that transports oxygen in most mollusks, some arthropods, and a few cephalopods. Hemocyanins are suspended directly in hemolymph. Compare hemoglobin.

hemoglobin (aka haemoglobin; abbreviated Hb or Hgb): the iron-containing oxygen-transport protein in red blood cells of almost all vertebrates except crocodile icefish. See icefish.

hemolymph (aka haemolymph): the fluid in the circulatory system of arthropods that is functionally analogous to blood and tissue fluid in vertebrates.

hematopoiesis: the production of blood. In a healthy adult, 10–11 new blood cells are made daily.

henbane (aka stinking nightshade, Hyoscyamus niger): an odorous angiosperm native to Eurasia. To discourage herbivores, every part of henbane is poisoned with a deliriant.

hepatic artery (aka proper hepatic artery): an artery that delivers oxygen-rich blood to the liver.

hepatic portal vein (aka portal vein): a blood vessel that conducts oxygen-poor but nutrient-rich blood from the gastrointestinal tract and spleen to the liver.

Hepatica (aka liverleaf, liverwort): a genus of herbaceous perennials in the buttercup family, native to central and northern Europe, Asia, and eastern North America. Hepatica was named for its leaves, which resemble the human liver in having 3 lobes. Owing to the Doctrine of Signatures, the plant was once wrongly thought to be an effective treatment for liver disorders. Although poisonous in large doses, the leaves and flowers are astringent, make for a salve for slow-healing injuries, and act as a diuretic.

heptane: a straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16.

herb: an herbaceous plant. Also used to refer to a leafy plant part employed as a food flavoring, medicinally, or in perfume. Compare spice.

herbaceous (plant) (shortened form: herb): an angiosperm that has leaves and stems which die down to the ground at the end of the growing season. Herbaceous plants have no persistent woody stem above ground. Herbaceous plants may be annuals, biennials, or perennials. Contrast arborescent.

herbivore: a heterotrophic organism that primarily eats plant-based foods. Compare omnivore, carnivore, and saprovore.

heredity (genetics): inheritance of traits from one generation of life form to the next.

hermaphrodite: a sexually reproducing organism with both male and female reproductive organs at some point in its life. Hermaphroditism is a normal condition for most invertebrates, which do not have separate sexes.

hermit crab: a crab of 1,100 species that salvages empty seashells for a protective lodging.

heroin: a morphine derivative.

heron: a long-legged freshwater and coastal bird of 64 species, some of which are called egrets or bitterns.

herpes: an ancient virus that causes disease in animals.

herpetology: the study of amphibians and reptiles.

Herrerasauridae: the order of the earliest dinosaurs, appearing in the fossil record 233 MYA, in the Late Triassic. Herrerasaurids were extinct by the end of the Triassic, leaving no descendants.

herring: a coastal, schooling, marine fish in the Clupeidae family.

hertz (Hz): the standard unit of frequency, defined as one cycle per second. The term hertz was first established by the International Electrotechnical Commission in 1930, though it was not until the 1970s that hertz universally supplanted its nomenclature predecessor, cycles per second.

heterofertilization: plant fertilization by sperms from different plants.

heterogamy (reproductive biology): sexual reproduction, as contrasted to parthenogenetic generation; in the context of alternation of generations. Contrast parthenogenesis.

heterokaryon: a special form of syncytium, in which a life form, such as a plasmodium, has multiple nuclei of different genetic origin.

heterokaryosis: the process of forming a heterokaryon.

Heterorhabditis bacteriophora: an entomopathogenic endoparasitic nematode that harbors Photorhabdus luminescens.

heterosporous: a plant with 2 spore sizes. Contrast homosporous.

heterothallism: a species with individuals having a single sex and practicing sexual reproduction only when opposite mating types come into contact. Heterothallic organisms are otherwise capable of asexual reproduction. The term is used to distinguish between fungi which require 2 compatible partners to sexually produce spores from homothallic ones which can sexually reproduce spores from a single organism. Contrast homothallism.

heterotopy: an evolutionary change in embryonic development spatially, which may be complementary to heterochrony.

heterotroph: an organism that cannot make its own food. All animals are heterotrophs. Compare autotroph.

heterozygous: different alleles at the same locus. Contrast homozygous.

heuristic (psychology): a simple, efficient rule employed to form judgments, solve problems, or make decisions. Compare algorithm. See affect heuristic.

hexapod: a 6-legged invertebrate.

hexavalent chromium (Cr(VI)): the element chromium in the +6 oxidation state. Hexavalent chromium is toxic and carcinogenic.

Hewlett-Packard (HP) (1938–): American electronics and computer company founded by Bill Hewlett and Dave Packard in 1939. In the 21st century, HP has suffered from mismanagement: stupidly acquiring companies at ridiculous prices rather than developing its own technology; a common death-rattle syndrome in technology companies after the bean counters take over.

heywood (Moricandia moricandioides): an herb in the Brassica genus, native to Spain.

hierarchy of needs: 5 levels of innate human needs proposed by Abraham Maslow: physiological, safety, love/belonging, esteem, and self-actualization.

hieroglyph: a pictographic or ideographic symbol used in a written language.

Higgs field: according quantum physics’ Standard Model, the universal field that imparts mass. Quanta hypothetically swim in the Higgs field, interacting at different strengths, and so maintain distinct masses, or are massless if the Higgs field fails to impress. The quantum representing the Higgs field is the Higgs boson. See Higgs mechanism.

Higgs field: according quantum physics’ Standard Model, the universal field that imparts mass. The quantum that represents the Higgs field is the Higgs boson. See Higgs mechanism.

Higgs mechanism: the continuous process whereby gauge (W & Z) bosons acquire mass via spontaneous symmetry breaking (SSB). The Higgs mechanism exemplifies the basic mechanism by which Nature is composed: universal fields localizing, with local fields quantizing into particulate form. The exposition of Ĉonsciousness works similarly: from universal to localized field (individual consciousnesses).

Hilbert space: a geometry capable of characterizing any number of dimensions. Named after David Hilbert by John von Neumann.

Himalayas: a young mountain range formed by the Indian subcontinent moving north and slamming into Eurasia. 9 of the 10 highest peaks on Earth are in the Himalayas.

hindsight bias (aka the knew-it-all-along effect): the tendency to see an event after it has occurred as predictable, despite little or no objective basis to view it as such beforehand. Compare future bias.

Hinduism: the dominant religion of India. Hinduism is based upon a compilation of diverse texts, the earliest of which date to the 7th century BCE , though most are later (late BCE). Such diversity means that Hinduism is an umbrella term, housing numerous religious offshoots.

hinny: a hybrid between a stallion and a female donkey. Compare mule.

hippocampus: a part of the brain in vertebrates associated with new memories and navigation.

hippopotamus: a large, mostly herbivorous even-toed ungulate of sub-Saharan Africa. Hippos are semiaquatic: inhabiting lakes, shallow rivers, and mangrove swamps. Despite resembling oversized pigs, their closest are cetaceans, from which they diverged 55 mya.

Hiroshima (Japan): a city on the southern part of Honshu, Japan’s largest island. Hiroshima was the target for the first nuclear holocaust, when the United States dropped an atomic bomb on it on 6 August 1945.

histamine (C5H9N3): a nitrogen-based biochemical which acts as a neurotransmitter and is involved in local immune responses and regulating gut functioning.

histology (aka microanatomy): the study of cell and tissue anatomy via microscopy.

histone: a highly alkaline protein in a eukaryotic cell nucleus that packages DNA into a nucleosome. Histones also act intracellularly as an antibacterial agent.

Hittites: an ancient Anatolian people who established an empire in north-central Anatolia 1600–1180 BCE.

HIV/AIDS (human immunodeficiency virus / acquired immune deficiency syndrome): an enveloped RNA retrovirus disease, termed for the immune system deterioration it causes, leading to AIDS, which is progressive immune system failure, allowing opportunistic infections and cancers to thrive. HIV is primarily transmitted via unprotected sex and blood transfers, such as contaminated transfusions and sharing hypodermic needles during drug abuse.

hive: a bee nest.

hoatzin (pronounced: wot-seen) (aka stinkbird, Opisthocomus hoazin): a pheasant-sized tropical bird found in swamps and riparian forest of the Amazon and Orinoco delta of South America. Hoatzin evolved in the Old World but made their way to the South America via floating on a raft of vegetation millions of years ago. European hoatzin died out when the climate became too cold.

hofragy (a portmanteau of hologram, fractal, and gyre; pronounced hō-fraj-eye): an interactive (gyral) holofractal.

hognose snake: a snake with an upturned snout, known for playing dead. There are 3 distantly related genera of hognose snake: in the United States and northern Mexico (Heterodon), South America (Lystrophis), and Madagascar (Leioheterodon).

holdfast: a root-like structure that anchors aquatic sessile organism, such as seaweed and sponges, to a substrate.

hole (physics): a conceptual absence of an electron in an environment where electrons are abundant. An electron excited into a higher state leaves a hole in former, less energetic state. Contrast positron.

holism: the idea that systems and their properties should be viewed holistically (from the perspective of being a whole), not just as a collection of components. Contrast reductionism. See synergy.

Holocaust (1941–1945): the genocide of Jews (6 million) (and others (5 million)) by the German Nazi regime during the 2nd World War.

Holocene (11,700 years ago–1940): the interglacial epoch during icehouse before Earth headed into hothouse from manmade pollution. The current hothouse epoch – the Omegacene – has yet to be recognized. The Pleistocene preceded the Holocene.

holofractal: a scale-invariant pattern that is self-similar but not selfsame to other holofractals of the same type.

holograph (aka hologram): an encoding of energetic interference patterns. { Spokes 4 }

holographic: semblances where components reflect the whole.

holographic principle: a conjecture, derived from string theories, that the universe is an information structure painted on a cosmological canvas, with energy and matter as incidentals.

hologram (aka holograph): an image made from recording interference patterns. As the pattern in a hologram is scale-invariant, each portion of a hologram has the same information content as the whole hologram.

holometabolous: a type of metamorphosis with 4 stages: egg, larva, pupa, adult. Compare ametabolous, hemimetabolous.

holy: devoted to goodness and having a divine quality.

Holy Ghost (aka Holy Spirit): the 3rd hypostasis of the Christian Triune God: Father, Son, and Holy Ghost, where each is a manifestation of God. The Holy Spirit is the active force (energy) of God.

Holy Roman Empire (962–1806): an empire ostensibly reviving the Roman Empire, in central Europe, between France and Poland, from northern Italy to the North Sea.

Otto the Great, having inherited the kingship of Germanic lands in 936, through further conquest consolidated the territories that would comprise the Empire. Otto was crowned Emperor by Pope John XII in 962. He would later have disputes with the papacy.

The Empire never achieved the level of political unification attained in France, which was its rival. The Holy Roman Empire was dissolved by the last Emperor, Francis II, who abdicated in 1806, after being defeated during the Napoleonic Wars.

Holy Trinity: the Christian doctrine that God manifests as 3 consubstantial hypostases: Father, Son, and Holy Ghost/Spirit.

Homeland Security: the US federal agencies responsible for fighting terrorism.

homeobox: a genetic sequence involved in regulating anatomical development.

homeodomain: a set of amino acids which confer a regulatory mandate to the proteins which contain them.

homeopathy: a pseudo-medicinal treatment of drinking water that has a specific substance diluted beyond measurement. Homeopathy can be effective via the placebo effect.

homeosis: the developmental transformation of one organ into another.

homeostasis (biology): a regulatory process by which an organism strives for holistic health. The term, from Greek, literally means “steady-state”: a rather ridiculous label to try to pin on a living organism, which cannot possibly maintain a constant status. Less mechanistic revision of the term from its original conception emphasizes the regulation inherent in maintaining health at whatever level the term is applied to: whether cellular, a specific internal system, or the whole organism. Compare autopoiesis.

homeostasis (physics): a tendency toward stability within a system.

homeotic gene (evolutionary development biology): a gene which regulates the development of anatomical structures via transcription factor programming, which affects genes in genetic regulatory pathways.

hominid: an ape descendant, some of which became hominin. Compare anthropoid.

hominin: the hypothesized clade that descended into humans.

hominoid: a primate of either hominid or anthropoid under the now obsolete Linnaeus system. Used herein for a primate with features that indicate evolution away from apes.

hominy: a food made from dried maize kernels soaked in an alkali solution, in a process called nixtamalization.

Homo (2.4 mya–now): a diverse genus of hominids which includes modern humans.

Homo erectus (2.5 mya–30 tya): a wandering hominin that emerged from Africa 2.0 mya to migrate to Europe, India, China, Indonesia, and possibly Australia.

Homo habilis (2.3–1.4 mya): a mostly vegan hominid and early tool maker.

homochirality: the geometry of something made of chiral units.

homogeneous: the same at all locations. Compare isotropic.

homolog (biology): a shared evolutionary ancestor.

homologous (chromosomes): duplicate chromosomes (having the same allelic genes). See homozygous.

homologous recombination: exchanging nucleotide sequences between similar genes. Contrast non-homologous recombination.

homologue (evolutionary biology): incremental evolution. Contrast analogue.

homoplasy: the seemingly same trait in organisms of different species, but the trait did not evolve from a common ancestor; instead, developed via parallel or convergent evolution.

homosexuality: proclivity for sexual activity with another of the same sex.

homosporous: a plant with a single spore size. Contrast heterosporous.

homothallism: a species where a single organism can sexually reproduce, as it has female and male reproductive structures on the same thallus. The term is commonly applied to fungi. Contrast heterothallism.

homozygous: selfsame alleles at the same locus on homologous chromosomes. Contrast heterozygous.

homunculus: a manikin (mannequin).

Honda (1937–): Japanese motorcycle, automobile, aircraft, and power equipment maker.

honesty: giving a candid impression. Contrast deception.

honey: a viscid sugar made by bees from nectar.

honey badger (aka ratel, Mellivora capensis): a weasel-looking mustelid native to Africa, southwest Asia, and the Indian subcontinent.

honey crop (aka honey stomach, honey sack): a specialized organ in the foregut of honeybees used to store and transport liquid food.

honey fungus (aka openky): a parasitic macroscopic fungus of woody plants in the genus Armillaria.

honey possum: a tiny marsupial (7–11 grams), half the weight of a mouse; native to southwestern Australia. The honey possum is a nectivore.

honeybee: a bee in 7 of 20,000 species of bees, in a subset of the genus Apis; best known for making honey via foraged pollen collection.

honeydew (secretion): a sticky, sugary liquid secreted by aphids and some scale insects.

honeyguide (aka honey bird): a near passerine brood parasite.

honeypot: an ant species where select workers are gorged with food by other workers. These engorged ants are then used as a larder by their sisters. A honeypot is solicited by stroking its antennae, whereupon it regurgitates some stored liquid. While many insects cache food, honeypot ants are unique in using their own bodies as a food store.

honor: integrity in one’s beliefs and actions; concern for a positive reputation about adhering to mores, notably honesty and fairness.

Honshū: the largest and most populous island of Japan.

hooded seal (Cystophora cristata): a large seal endemic to the central and western North Atlantic Ocean.

hookworm: a parasitic nematode that lives in the small intestine of its mammalian host.

horizon (pedology): a soil layer.

horizon problem (aka homogeneity problem): the conundrum that the cosmic microwave background exhibits a uniformity which cannot be explained by known physics.

horizontal gene transfer (HGT): sharing of genetic material between organisms. Contrast vertical gene transfer.

hormone: an organic compound intended for long-distance intercellular communication; from the Greek word for impetus.

Horn of Africa: a peninsula in easternmost central Africa which juts into the Guardafui Channel, the oceanic strait which connects the Gulf of Aden to the north with the Indian Ocean to the south. The tip of the Horn of Africa is Cape Guardafui.

hornbill: a tropical or subtropical bird in the Bucerotidae family, found in Africa, Asia, and Melanesia. Hornbills have a large, long, downward curving bill, sometimes with a casque (protrusion) on the upper mandible.

horned frog: a frog with a flap/horn of skin above each eye.

hornwort: a group of bryophytes that evolved during the Devonian, now of 100–150 species, found worldwide in moist soils.

horology: the study of timekeeping.

horse (Equus ferus caballus): an odd-toed ungulate. Men began to domesticate horses ~4,000 BCE. See equid.

Horus: one of the oldest and most important deities in ancient Egyptian religion; the god of the Sun, war, and safety.

host (biology): a cell, virus, or organism in/on/to which another organism has an interest or relationship.

host cell: a cell hosting an endosymbiont. Eukaryotes arose from an archaeon hosting one or more bacterial endosymbionts.

host dependency factor: a cellular component that a virus needs to survive, replicate, or spread.

host range: the cell type(s) that a virus infects by recognizing cell surface receptors.

hostile attributional bias: the tendency to perceive hostile intent by others irrespective of indication.

hot-cold empathy gap: see empathy gap.

hot hand: the bias that success continues in a streak.

hothouse (aka greenhouse): a duration lasting millions of years where Earth is hot and typically humid, completely lacking continental glaciers. Contrast icehouse.

house dust mite: a homebody mite, found even in the cleanest house. House dust mites select food already partly decomposed by fungi, as they literally have no stomach for digestion.

house finch (Haemorhous mexicanus): a small residential (non-migrating) songbird now found throughout the US and much of Mexico, and in southern Canada.

house mouse (Mus musculus): a mouse that mainly lives in association with humans.

House of Plantagenet: a royal British house which originated in the lands of Anjou, in northwestern France. The family held the English throne from 1154. Its reign planted the seeds of democracy that evolved in England, beginning with royal charters, notably the Magna Carta.

housefly (Musca domestica): a fly that is one of the most widely distributed insects, found all over the world. Adult houseflies are 5–8 mm long. Houseflies live up to their name: most flies found in human domiciles are houseflies. The ones not in the house want in. The housefly evolved 50 MYA on the steppes of central Asia and spread worldwide as a human commensal.

housekeeping gene: a coding sequence for a basic cellular function, expressed in all cells of an organism.

hoverfly (aka flower fly, syrphid fly): a fly of ~6,000 species in 200 genera, in the Syrphidae family; often seen hovering over nectaring flowers.

howler monkey: a large New World monkey of 15 species in the Alouatta genus, known for its loud howl, which can carry 5 km through dense forest.

HP: see Hewlett-Packard.

html (HyperText Mark-up Language): a tag-based markup language for displaying document pages; the standard language for web page display on the World Wide Web.

Hubble’s law: a cosmological observation that deep space objects are observed via a Doppler shift relative to Earth, owing to their receding (moving away) from Earth.

Hubble sequence: a classification of galaxies by their appearance (visual morphology), devised by American astronomer Edwin Hubble in 1926.

Hubble Space Telescope: a 2.4-meter aperture telescope carried into Earth orbit by a US space shuttle in 1990.

Hugenot: a 16th–18th century French Protestant inspired by the writings of John Calvin (Calvinism).

human (Homo sapiens): a bipedal, largely furless primate. Humans are ironically unintelligent in thinking that they are smarter than other organisms while having proved the opposite with their self-destructive and environmentally devastating behaviors.

human capital: the idea of people as productive labor units.

Human Rights Watch (1978–): an international non-governmental organization dedicated to human rights under sway of natural law principles.

humanism: an ethical stance emphasizing the value of human beings. The meaning of the term has fluctuated. In modern times, humanism is associated with secularism.

humanistic psychology (aka humanism): a school of psychology emphasizing personal drive to productive expression, developed by Abraham Maslow in the late 1950s (albeit based upon ancient philosophic precepts). The humanist premise is that people are inherently well intentioned. The humanistic perspective was termed third-force psychology by Abraham Maslow in 1962, referring to psychoanalysis and behaviorism as the other 2 predominant contemporaneous schools of psychology.

Humboldt Current (aka Peru Current): a cold, low-salinity deep-water ocean current flowing northwestward along the west coast of South America, from the southern tip of Chile to northern Peru. The current ends its flow going east near the equator, extending to 1,000 km offshore (the Galápagos Islands). The Humboldt Current provides for the most productive marine ecosystem in the world, as well as being the largest upwelling current. It also cools the lands that it runs by: Chile, Peru, and Ecuador. Through fog and clouds are produced, marine air cooled by the Humboldt Current is not conducive to generating rain, which so accounts for the aridity in the coastal areas where it flows.

Humboldt squid (aka jumbo squid, pota, diablo rojo, Dosidicus gigas): a large, bioluminescent predatory squid living in the depths of the Humboldt Current in the eastern Pacific Ocean.

hummingbird: a bird in the Trochilidae family. Hummingbirds are among the smallest of birds, including the smallest: the 5 cm Bee Hummingbird.

humor: an amusing incongruity.

humor (biology) (aka humour): according to the abandoned doctrine of humorism (aka humoralism) a bodily fluid that directly influences health and temperament. The 4 humors of Hippocratic humorism were blood, phlegm, black bile, and yellow bile, each corresponding to the 4 temperaments (sanguine, phlegmatic, melancholic, and choleric, respectively). Humor imbalance produce personality inclination.

humus (soil): amorphous soil; the organic portion of soil, formed from partial decomposition of plant and animal matter. Humus contributes to the retention of nutrients and moisture.

Huntington’s disease: a degenerative disease affecting muscle coordination, leading to cognitive decline and mental problems.

Hugenot: 16th–18th century French Protestants inspired by the writings of John Calvin (Calvinism).

Hundred Years’ War: see 100 Years’ War.

Hungary: a central European country, run as a parliamentary democracy.

Huronian glaciation (aka Makganyene glaciation) (2.4–2.1 bya): a global glaciation following the Great Oxygenation Event .

Hutterites: a religious group of Anabaptists that practiced socialism and pacifism, founded by Jacob Hutter.

Huygens–Fresnel principle: a verified mathematical characterization of wave propagation by Christiaan Huygens (1678) and Augustin Fresnel (1818). See principle of least action.

hybrid: an organism that is a combination of 2 species.

hydrocarbon: an organic compound entirely comprising hydrogen and carbon. Methane (CH4) is an exemplary hydrocarbon.

hydrocephalus: an accumulation of cerebrospinal fluid within the brain.

hydrochloric acid (HCl): a clear, colorless, highly pungent solution that is highly corrosive. Hydrochloric acid has many industrial uses.

hydra: a genus of freshwater invertebrates of ~25 species, with a body consisting of a thin, typically translucent tube up to 30 mm long.

hydrogen (H): the element with atomic number 1, constituting in its simplest form a single proton and solitary electron (protium, 1H); the lightest element, and the most abundant chemical in the universe, comprising 75% of cosmic baryonic mass. Hydrogen plays an important role in acid-base chemistry. Hydrogen is a proton donor in many reactions between soluble molecules.

hydrogen bond: a chemical bond between a hydrogen atom and either an oxygen, nitrogen, or fluorine atom in a molecule. Water is exemplary of hydrogen bonding.

hydrogen chloride (HCl): a colorless, corrosive gas.

hydrogen sulfide (H2S): a colorless gas with the foul odor of rotten eggs. H2S is poisonous, corrosive, and flammable.

hydrogenation: the process of turning an unsaturated fat into a saturated one via high-temperature heating.

hydrolase: an enzyme that catalyzes hydrolysis.

hydraulic lime: lime used to make mortar.

hydrological cycle (aka water cycle): the cycling of water in the biosphere.

hydrolysis: (in context) a reaction that breaks a biopolymer down in the presence of water and an enzyme. Broadly, a chemical reaction in which water molecules (H2O) are split into hydrons (H+) and hydroxyls (OH).

hydron: a hydrogen cation (H+).

hydronium (H3O+): an ion that is essentially water (H2O) with a hydrogen hanger-on.

hydrophilic: having a high affinity for water. Contrast hydrophobic.

hydrophobic: having a low affinity for water. Contrast hydrophilic.

hydrophyte: a plant adapted to living in waterlogged soil or in water.

hydrosphere: the bioelement of water, including the participants in the water cycle.

hydrostatic pressure: the pressure exerted by a fluid at equilibrium because of gravity.

hydrothermal vent: a fissure, usually on the seabed at a volcanically active location, from which geothermally heated water issues.

hydroxide: a chemical compound with a hydroxyl group.

hydroxyl (OH): a functional group comprising an oxygen atom covalently bonded to a single hydrogen atom. Compare water (H2O).

hydrozoan (plural: hydrozoa): a diverse group of tiny, predatory, mostly marine animals, found worldwide. Different hydrozoa live solitary or colonial lives.

hyena: a dog-like carnivorous mammal that arose in Eurasia during the Miocene 22 mya and developed into 2 distinct groups: robust bone-crunchers and lightly-built dog-like creatures more given to scavenging. Extant hyenas live in Africa and Asia.

Hyksos: a tribe from west Asia who took over the eastern Nile Delta around 1800 BCE.

hylomorphism: the belief that all things are a combination of matter and form. The form of life is in the soul. Aristotle concocted hylomorphism.

hylozoism: the hypothesis that all matter is in some sense alive.

Hymenoptera: one of the largest orders of insects, including ants, bees, wasps, and sawflies; derived from the Greek word for wing. Hymenoptera range in size from tiny to quite large. They have large compound eyes. Their mouths are adapted for chewing. Hymenoptera typically have 2 pairs of wings. The sex of almost all hymenopterans is decided by the number of chromosomes an individual has. Fertilized eggs get 2 sets of chromosomes (from mother and father), developing into diploid females. Unfertilized eggs, with only the mother’s chromosomes, develop into haploid males. Fertilization is volitionally controlled by the egg-laying female. This is known as haplodiploidy.

hymn: a religious song written in adoration of a deity or deities. A person who writes hymns is a hymnodist.

hyoid apparatus: the bones or cartilage which suspend the tongue, and in mammals the larynx.

hyperinflation: a rapid debasement of a currency which destroys its purchasing power. Compare inflation.

hyperlipidemia: an abnormally elevated level of lipids in the blood.

hypernova: an exceptionally large supernova: at least 140–200 solar masses, which entirely explodes, leaving no core material.

hyperon: a 3-quark particle comprising up, down, and strange quarks; formed within a neutron star turning into a quark star.

hyperpallium (aka hyperstriatum): the portion of an avian brain analogous to the mammalian cerebral cortex.

hyperphagia: intensive feeding; one way that migratory animals prepare themselves for their journey.

hyperplasia: growth in a tissue or organ by cell proliferation. Contrast hypertrophy.

hyperpolarization (biology): a change in a cell’s membrane potential that makes it more negative. Contrast depolarization.

hyperthermophile: an organism that can survive at 80°C or greater.

hypertrophy: growth in a tissue or organ by cell enlargement. Contrast hyperplasia.

hyperuniformity: regularity in density fluctuations in a many-body system. Disordered structures at small scales which possess a “hidden order” at larger scales are hyperuniform.

hypha (plural: hyphae): a threadlike fungal filament.

hypoglycemia: an abnormally low level of blood sugar.

hyposmia: diminished sense of smell. Compare anosmia.

hypostasis: an underlying state or substance of fundamental reality that supports all else.

hypothalamus: a brain region found in all vertebrates. The hypothalamus controls body temperature and regulates episodic biological imperatives (circadian rhythms), such as thirst, hunger, fatigue, sleep, and mating and parenting behaviors.

hypothermia: low body temperature. Compare euthermia.

hypothesis: a guess gussied up in scientific garb. Under the scientific method, hypotheses are ripe for falsifiability testing. Compare theory.

hypoxia: a deficiency of oxygen reaching body tissues. Compare anoxia.

Hypsilophodont: a genus of relatively small (1–2 meter), agile, bipedal, herbivorous ornithopods.

hyrax (aka dassie): a small, thickset, herbivorous mammal, endemic to sub-Saharan Africa and the Middle East. Adults weigh 2–5 kg and are 30–70 cm long. Hyraxes retain a number of early mammalian characteristics. They are barely endothermic: needing to huddle together for warmth, or bask in the Sun. Like rodents, hyrax teeth constantly grow, but they do not use their front incisors for biting. Instead, they use their side molars. Although not ruminants, their digestive tract is like those of ungulates, as hyraxes have complex, multi-chambered stomachs which allow symbiotic bacteria to break down fibrous plant matter. Though they bear no resemblance, the hyrax is a close relative to the elephant.

hysteria: a colloquial term for unmanageable emotional distress.