Glossary – L

L

La Niña: the opposite Pacific Ocean dynamic to El Niño.

L-form (state): a mode of existence for a bacterium of not having a cell wall (which most bacteria have).

labellum: a special petal at the bottom of an orchid flower which attracts pollinating insects and acts as a landing platform.

Labour Party: the dominant centre-left party in the UK. Contrast Conservative Party.

Laccaria bicolor: an ectomycorrhizal fungus that appears a small tan mushroom with lilac gills.

lacerta (aka true lizard, wall lizard): a lizard in the Lacertidae family, comprising over 300 species in 29 genera, native to Africa, Europe, and Asia.

Lacerta (astronomy) (aka Lizard): one of the 88 modern constellations; Latin for lizard; conceived in 1687 by Johannes Hevelius.

lactase: an enzyme essential to break down lactose, the complex sugar found in milk.

lactate (C3H6O3 aka lactic acid): a compound employed in various biochemical processes, including brain metabolism.

Lactobacillus: a genus of rod-shaped, non-spore-forming bacteria which is either anaerobic or microaerophilic. Lactobacillus can convert lactose and other sugars to lactic acid.

lactose (C12H22O11): the disaccharide sugar found in milk.

laetrile: a modified form of amygdalin, promoted since the early 1950s as a cancer cure.

Lagrangian: the mathematical function of Lagrangian mechanics.

Lagrangian mechanics: a 1788 reformulation of classical mechanics by Joseph-Louis Lagrange.

laissez-faire: the doctrine that government should not interfere in commercial affairs.

Lake Duck (aka Argentine Blue-bill, Oxyura vittata): a small, South American stiff-tailed duck.

Lake Tanganyika: a large lake in Africa; the world’s longest freshwater lake, the 2nd-oldest, 2nd-largest by volume, and 2nd-deepest (in all instances after Lake Baikal in Siberia). Tanganyika refers to “great plain-like lake.”

Lake Rudolf: a lake in Kenya, now called Lake Turkana.

Lamarckism (aka Lamarckian inheritance, heritability of acquired characteristics, soft inheritance): the theory that an organism can pass on characteristics acquired during its lifetime to its offspring. Named after Jean-Baptiste Lamarck, who proposed the hypothesis. Long disparaged by Darwinists, the discovery of epigenetics has validated Lamarckism.

Lamb shift: an energy difference between 2 energy levels of the hydrogen atom, according to quantum electrodynamics. Named after Willis Lamb.

Lambda cold dark matter model: see ΛCDM (under A because Λ looks like an ersatz A).

lambda point: the triple-point temperature below which fluid helium turns into superfluid helium: 2.172 K at 1 atmosphere (101,325 Pa).

lamella (surface anatomy) (plural: lamellae): a thin, plate-like structure. Fish gills and gecko feet use lamellae to achieve their respective functionality.

lamina propria: a thin layer of connective tissue that is part of the moist linings of mucous membranes.

lamprid: a ray-finned fish in the Lampriformes order that are pelagic feeders, typically brightly colored, often with brilliant crimson fins. Lamprid body forms vary but are generally compressed laterally.

lancelet (aka amphioxus): a fish-like marine chordate of ~32 extant species.

Landau–Fermi liquid theory: a theoretical model of fermion interactions for most metals at low temperatures. The theory explains why some properties of an interacting fermion system are selfsame to those of the Fermi gas (i.e., non-interacting fermions), and why other properties differ.

language: a system of symbols with interrelated meanings.

langur: a general name given to several Asian monkey species.

Lanikea: the galactic supercluster in which the Milky Way galaxy resides.

lanternfish (aka myctophid): a small, mesopelagic (twilight zone) fish in the Myctophidae family, with 33 genera and 246 species. All but 1 species of lanternfish are bioluminescent.

lanthanum (La): the element with the atomic number 57; a soft, ductile, silvery-white metal which rapidly tarnishes when exposed to air and is so soft as to be easily cut with a knife.

Laplace’s demon: the idea that existence would be utterly predictable (deterministic) to an intellect (the demon) that was omniscient; posited by Pierre-Simon Laplace in 1814.

large blue butterfly (Maculinea arion): a gossamer-winged butterfly native to northern Eurasia that deceives red ants (Myrmica sabuleti).

Large Hadron Collider (LHC): the most powerful particle collider and the largest machine in the world; built 1998–2008. The LHC lies in a tunnel 27 km in circumference and as deep as 175 meters beneath the France-Switzerland border near Geneva.

large intestine: the last part of the gastrointestinal tract in vertebrates, including the cecum, colon, rectum, and anal canal. The colon is the largest portion of the large intestine.

lark: a passerine in the Alaudidae family, with 21 genera; extant in the Old World, and in eastern and northern Australia. The horned lark is found in North America. Many larks live in dry biomes.

lark bunting (Calamospiza melanocorys): a medium-sized sparrow native to central and western North America.

larva (biology) (plural: larvae, larvas): the immature, wingless, and often wormlike (vermiform) feeding stage of a holometabolous insect hatched from an egg. The next development stage is as a pupa. Compare nymph.

larynx (aka voice box (for humans) ): a hollow tube connected to the top of the trachea in tetrapods; used for breathing, sound production, and protecting the trachea from food aspiration.

Last Glacial Maximum (26.5–19.5 tya): the last period of peak glaciation on Earth.

Late Antiquity (284–650): the transition period from classical antiquity to the Middle Ages, applicable to both mainland Europe and the Mediterranean region.

late blight: a potato blight caused by Phytophthora infestans. In small contrast, early blight is caused by Alternaria solani, another fungus. The term early is a misnomer, as it usually occurs on older potato plant leaves.

latent heat: how much thermal energy (heat) can be absorbed or released by a body without changing the body’s temperature.

lateral line: a sense organ system in aquatic vertebrate, chiefly fish, used to detect movement via vibration.

lateral meristem: a meristem which grows a plant larger in diameter.

lateralization (avian vocalization): separate sounds from each bronchus.

lateralization (brain): functioning largely specific to the left or right hemisphere of the brain.

lattice: a mathematical construct of symmetrical order within a group . In physics, a lattice is a lattice-like physical model. In chemistry, a lattice is a solid arranged into a lattice.

lattice constant (aka lattice parameter): the physical dimensions of unit cells in a crystal lattice.

Laurasia: the northernmost of 2 supercontinents that split from the supercontinent Pangea 200 MYA. Laurasia included most of the current continental landmass of the northern hemisphere. Gondwana was the southern portion of erstwhile Pangea.

laurel forest (aka laurisilva): a subtropical forest type with high humidity and relatively stable, mild temperatures. Laurel forests are dominated by broadleaf trees with glossy, evergreen, elongated leaves, known as lauroid or laurophyll.

Laurentia: a large continental craton created 1.5–1.0 bya; now the North American Craton, after much movement and rotation. The craton now comprises eastern and central Canada, and most of the middle states of the United States. PreCambrian basement rock at the southwest portion of the craton was deformed by continental collisions, begetting the Rocky Mountains.

Laurium, Greece: a coastal town in Southeast Greece, founded before the 11th century BCE, famed for its silver mining.

law (natural philosophy): a conclusion about a universal tendency in Nature.

law (polity): a legally codified norm or proscription against a taboo; state codification aimed at administering justice and the affairs of the state to which the law pertains.

law of contrapositive (aka denying the consequent or modus tollens): deductive reasoning, wherein a conditional statement determines whether a hypothesis is invalid. See law of detachment, law of syllogism.

law of demand: the idea that demand falls when the price of a good goes up; an inverse relationship between price and quantity demanded, rendering a downward-sloping demand curve.

law of detachment (aka affirming the antecedent or modus ponens): deductive reasoning, wherein a conditional statement determines whether a hypothesis is valid. See law of contrapositive, law of syllogism.

law of effect: the theorem that the outcome of an action determines the likelihood that it will be repeated; posited by Edward Thorndike in 1905.

law of exercise: the theorem that the strength of association between a stimulus and response depends on the number of its repetitions and the strength of their pairing; posited by Edward Thorndike in 1911.

law of independent assortment: a hypothesis by Gregor Mendel that the expression of any 1 genetic trait is not influenced by another. This so-called law is bogus.

law of large numbers: a statistical theorem which states that the average result should come closer to the expected value with larger sample size or greater number of repetitious experimental results.

laws of motion (Newton’s): 1) a body has constant velocity unless acted upon by an external force; 2) acceleration is proportional to force and inversely proportional to mass; and 3) the mutual forces of action and reaction between 2 bodies are equal, opposite, and collinear.

law of Prägnanz: the Gestalt principal that ambiguous or complex images are perceived in the simplest possible form because it requires the least cognitive effort.

law of primogeniture: a law providing statutory preference of offspring inheritance, particularly real estate; in Britain, the first-born son is the sole inheritor.

law of segregation: an observation by Gregor Mendel that an allele in a diploid organism may express as dominant, masking a recessive allele that would express a different trait.

law of syllogism: deductive reasoning, wherein 2 premises and are combined into a conclusion. See law of detachment, law of contrapositive.

laws of thermodynamics: classical physics laws related to heat energy and entropy. The laws of thermodynamics all assume a universe that is an energetically closed system 4D. This presumption renders the laws fictional, because the cosmos has extra spatial dimensions (ED), with a constant energy exchange 4D and ED. Nonetheless, physicists still take these laws seriously, as they are taught as being cardinal. The laws of thermodynamics do provide proximate results at the ambient scale where they are typically applied.

leaching layer: the uppermost soil horizon, where organic debris breaks down and is washed downward into the middle soil layer by rainwater.

lead (Pb): the element with atomic number 82; a bright, silvery, soft, malleable metal that is extremely toxic. Lead is the heaviest non-radioactive element.

leaf: a vascular plant organelle, typically employed in photosynthesis. Leaves evolved to suit plants specific needs, optimized to constraints imposed by physics at the quantum level. See foliage.

leaf beetle: a beetle in the Chrysomelidae family, with over 50,000 species; one of the most commonly encountered beetles.

leaf monkey: an arboreal Asian monkey with a slender body and long tail.

leafcutter ant: a tropical leaf-chewing, fungus-farming ant. There are 47 non-generic species that go by the leafcutter name.

leafhopper (aka hopper): a small (up to 1.5 cm), slender, winged insect of 20,000+ species in the Cicadellidae family, named for their hopping ability. Leafhoppers suck plant sap for food.

League of Nations (1920–1946): a supranational organization between the 1st and 2nd World War; ineffective for lack of support by member nations, and especially by the failure of the United States to join.

learning: the process of constructing a conceptual framework.

learning curve: (literally) a graphical curve plotting performance against experience; (figuratively) the challenge or rate of learning a skill. For instance, a steep learning curve means either requiring an immersive or extensive experience to learn (challenge) or learning very quickly (rate of learning).

least weasel (Mustela nivalis): the smallest weasel, but a fierce hunter, able to bring down a rabbit 5–10 times its weight. Least weasels are native to Eurasia, North Africa, and North America.

lechwe: an African antelope, with adults 90–100 cm high at the shoulder, 70–120 kg. Herds, which may number many thousands, are usually a single sex. During breeding season, herds mix. While almost all females breed, only dominant males do. Males battle for mating privilege.

lecithin: a yellow-brownish amphiphilic fat found in plant and animal tissues.

lectin: a carbohydrate-binding protein.

leech: a clade of segmented worms. Most are blood suckers.

left wing: a political philosophy supporting social equality and egalitarianism, typically opposed to social stratification. Contrast right wing.

left-brain/right-brain hypothesis: the false idea that the left hemisphere of the brain is rationally analytic, while the right hemisphere is emotive and creative.

legato (music): smooth, connected notes. Contrast staccato.

leghemoglobin: a protein that carries nitrogen or oxygen in plants.

Legionnaires’ disease: an atypical pneumonia caused by the freshwater Legionella bacterium.

legume: an herbaceous perennial plant or its fruit or seed. Well-known edible legumes include alfalfa, beans, carob, lentils, peanuts, peas, and soybeans.

Lehman Brothers (1850–2008): American investment bank that was the 4th-largest such bank months before it declared bankruptcy for its participation in the mortgage securities bubble that burst in 2008.

lek: a gathering of animal males for competitive courtship display.

lemur: a clade of prosimian, named after the lemures (ghostly spirits) of Roman mythology, owing to lemurs’ ghostly vocals, reflective eyes, and often nocturnal lifestyle. Lemurs are endemic to Madagascar, having arrived by rafting 62–65 mya. Some lemurs were as large as male gorillas until after humans arrived on the island 2,000 years ago. The invasive humans wiped the large lemurs out.

length contraction: a moving observer perceiving the length of an object decreasing.

lengyre (aka vital energy, chi (Chinese), prana (Hindu)): an organism’s life-energy gyre.

lens (biology): the transparent, biconvex eye structure that helps to refract light to focus on the retina.

lenticel: porous tissue that allows gas exchange between internal plant tissues and the atmosphere.

Lepiotaceae (fungus): a family of fungi that have a mutualism with leafcutter ants.

leprosy: a bacterial infection with progressive symptoms that can permanently damage the skin, limbs, eyes, and nerves.

leopard ground squirrel (aka 13-lined ground squirrel, striped gopher, squinney, Ictidomys tridecemlineatus): a ground squirrel widely distributed over the prairies and grasslands of North America, with 13 alternating brown and whitish longitudinal lines (sometimes broken into spots) on its back and sides.

lepidopteran: an insect in the diverse Lepidoptera order which includes moths and butterflies.

lepton: a subatomic particle not subject to the strong force. Electrons, muons, and neutrinos are leptons.

Levant: the geographical region encompassing modern-day Jordan, Israel, Lebanon, and Syria. The term Levant first appeared in English in 1497; originally meaning “the East.” The Levant has been characterized as the “crossroads of western Asia, the eastern Mediterranean and northeast Africa.”

lettuce (Lactuca sativa): a leafy, green vegetable in the sunflower family.

leukocyte (aka white blood cell): an immune system cell in the blood.

Levant: the geographical region encompassing modern-day Jordan, Israel, Lebanon, and Syria.

Levant: the geographical region encompassing modern-day Jordan, Israel, Lebanon, and Syria. The term Levant first appeared in English in 1497, originally meaning “the East.” The Levant has been characterized as the “crossroads of western Asia, the eastern Mediterranean, and northeast Africa.”

leverage (aka gearing (UK, Australia)) (finance): any technique aimed at acting as a financial multiplier. Most often leverage involves buying more of an asset via borrowed funds.

leveraged loan: a loan to an individual or company with a poor credit history and/or already carrying considerable debt.

levulinic acid (CH3C(O)CH2CH2CO2H): an acid derived from cellulose degradation.

Lévy walk (aka Lévy flight): a random walk defined by step lengths. The term was coined by Benoît Mandelbrot, referring to Paul Lévy.

lexical: relating to words or vocabulary as distinguished from grammar.

Lewis acid: a substance that can accept a pair of nonbonding electrons – an electron pair acceptor. Lewis acids and bases were suggested by Gilbert Lewis. Contrast Lewis base.

Lewis base: a substance that can donate a pair of nonbonding electrons – an electron pair donator. Contrast Lewis acid.

liability (finance): a debt or obligation. Contrast asset.

liana: a woody vine, rooted in the soil, that climbs trees to the canopy.

liberalism: historically, a political philosophy advocating the freedom of individuals, albeit with some concern for social equality. Classical liberalism stressed liberty (libertarianism), whereas later social liberalism sought a balance between liberty and social justice. The term neoliberalism refers to a strain of laissez-faire economic liberalism that arose in the 1970s. In Spokes, liberal or liberalism is used in the classical sense (in historical context), but when discussing modern ideologies, social liberalism is intended, with its principle concern of societal equity. Compare radicalism, conservatism, reactionism.

Liberibacter: a bacterium that infects citrus trees.

Libertarian Party (United States) (1971–): American political party favoring minimal government and laissez-faire capitalism.

libertarianism (historically classical liberalism): a political philosophy that places individual liberty as its principle objective.

Libor (London Interbank Offered Rate, aka LIBOR) (1984–): a set of interbank lending rates set by banks; originated in England.

Libya: a country in the Maghreb.

lichen: a composite organism comprising a fungus (mycobiont) and a photosynthetic (photobiont) cyanobacterium or algae.

licorice (aka liquorice): the root of the perennial herb Glycyrrhiza glabra, native to southern Europe and parts of Asia; popular in candy and used as a flavoring agent for tobacco.

life: anything capable of perceiving its environment.

life-history variable: a trait or aspect of an organism’s existence related to others; often viewed comparatively, as a trade-off with other, mutually exclusive possibilities.

life space (aka psychological field): the hypothesis by Kurt Lewin that a person’s current behavior reflects the aggregation of personal experiences.

life zone: according to a biome classification scheme by Leslie Holdridge, a region with similar soil type and climax vegetation (dominant plants).

ligand (biochemistry): a molecule that emits a signal by binding to a site on a target protein.

light: electromagnetic radiation visible to the human eye, at a wavelength between 380–740 nanometers.

light matter: ordinary matter. Contrast dark matter.

light-year: how far light travels in a year at light-speed (as fast as light can travel); the standard unit used to express astronomical distances. A light-year is ~9.461 trillion kilometers.

lignin: an amorphous polymer related to cellulose. Lignin is an integral part of the cell walls of plants and some algae.

lignotuber: a woody swelling of the root crown in some plants, as a protection against plant stem destruction, such as by fire.

ligule: a thin outgrowth at the junction of a leafstalk and leaf in a grass or sedge. The ligule is at the junction of the blade and sheath of a leaf.

lilac: a flowering woody plant in the Syringa genus of the olive family, with 20–25 species, endemic to temperate Eurasia.

lily: an herbaceous angiosperm which grows from bulbs. There are at least 111 species in the Lilium genus. All have large prominent flowers. Numerous plants with the lily name are not true lilies.

lima bean (aka butter bean): a legume.

limbic system (aka paleomammalian cortex): a diverse set of brain structures in the frontal lobe, including the olfactory bulbs, hippocampus, amygdala, and cingulate gyrus. These areas are involved in olfaction, emotion, motivation, behavior, and memory. The notion of a limbic system is considered archaic by some, as it relies upon anatomical relations no longer considered accurate.

lime: a calcium-based inorganic material. Lime is nominally calcium oxide (CaO). A close relation is slaked lime (calcium hydroxide (Ca(OH)2)).

limestone: a sedimentary rock, largely comprising calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Many limestones are the compressed remnants of marine organisms, such as coral and foraminifera.

limited liability: a legal circumscription of financial liability.

linear (chemistry): a molecular shape created by a central atom surrounded by 2 electron groups having bonding angles of 180°.

linear equation: an equation with 2 variables.

linguistic relativity hypothesis (aka Sapir-Whorf hypothesis): a hypothesis asserting that the structure of human language affects how native speakers conceptualize the world.

linguistics: the study of language.

Linnaeus: a long-accepted biological classification system proposed by Carl Linnaeus in the mid-18th century.

linoleic (LA): an essential omega-6 fatty acid.

Linux (1991–): a Unix-like OS, with a kernel developed by Linus Torvalds .

lion: a large cat in the Panthera genus. Lions were endemic to Africa and Eurasia until hunted by humans to extinction in all but Africa, where they are increasingly endangered by the same dynamic.

lionfish: a venomous marine fish in the Pterois genus.

lipase: an enzyme that catalyzes the metabolic breakdown of lipids.

lipid: a broad group of relatively complex nonpolar carbon-based compounds, used for energy storage and a wide variety of biological functions.

lipid droplet: a ubiquitous cellular fat storage organelle for energy production and as a biosynthetic precursor.

lipogenesis: conversion of carbohydrates into triglycerides.

lipophilic: having a high affinity for lipids.

lipopolysaccharide (aka lipoglycan): a lipid and a polysaccharide joined by a covalent bond.

lipoprotein: a lipid and protein combined.

liquid: a fluid that flows freely. Water is a liquid at room temperature.

liquid crystal: matter in a state with properties of both liquids and crystals.

liquidity (finance): the ease with which an asset can be converted into cash; more loosely used to express the financial environment in terms of money availability.

Lisp (acronym for List Processor): a high-level computer programming language, first specified in 1958; long a favored language for artificial intelligence programming.

listening: paying attention to sound.

listeriosis: a foodborne infection caused by Listeria bacteria.

lithium (Li): the element with atomic number 3; a soft, silvery-white alkali metal. Under ambient conditions lithium is the lightest solid. Lithium is highly reactive and flammable.

lithotroph: an organism that consumes inorganic minerals.

lithosphere: the outermost shell of a rocky planet. Earth’s lithosphere comprises its crust and upper mantle: the portions that behave elastically over geological expanses of time.

Little Ice Age (1300–1850): an extended period of planetary cooling. Though the Little Ice Age began ~1300, there were 3 particularly cold intervals: the 1st beginning in ~1650, the 2nd ~1770, and the last in 1850. Slight warming separated these lengthy cold snaps.

littoral zone (aka nearshore): the area close to shore of a river or body of water.

liver: a vital digestive system organ in vertebrates. The liver has a wide range of functions, notably detoxification, protein synthesis, and the production of digestive biocompounds.

liverwort (aka Marchantiophyta): a non-vascular embryophyte.

lizard: a scaled reptile of over 5,600 extant species in all continents except Antarctica, including most oceanic islands.

loam: soil which is roughly 40% sand, 40% silt, and 20% clay. Loam soils generally contain more plant nutrients, moisture, and humus than sandy soils, and offer better drainage and water and air infiltration than silt or clay soils, as well as being easier to till than clay soils.

loan: money lent at interest.

lobe-finned fish (Sarcopterygii): a clade of bony fish with fleshy, lobed, fin pairs, joined to the body by a single bone. Each fin is on a scaly stalk extending from the body. Contrast ray-finned fish.

lobster: a large marine crustacean with 5 pairs of legs, a long body and muscular tail. Lobsters are found in all oceans, residing in burrows or crevices on the sea floor. Lobsters may live 40–60 years, possibly more.

locality (physics): the idea that an object can only be influenced by its immediate surroundings. See entanglement. Contrast nonlocality.

localization (biochemistry): control of allosteric regulation at a specific position on a protein via specific molecular binding configuration (sequence).

localization (physics): the process of locally confining or effecting a result from a universal field.

Lockheed (1926–): American aerospace company which merged with Martin Marietta to form Lockheed Martin in 1995.

locus (genetics): a gene’s position in a genophore or chromosome.

locust: a short-horned grasshopper that has a swarming phase. Several grasshopper species go locust on all continents except North America and Antarctica. The desert locust (Schistocerca gregaria) is best known: swarming in north and west Africa, the Middle East, and the Indian subcontinent. The migratory locust (Locusta migratoria) swarms in Africa, Asia, Australia, and New Zealand.

loess: an unstratified loamy deposit, usually yellowish brown, carried by the wind. Loess is found in Asia, Europe, and North America.

logarithm: the inverse operation to exponentiation; a number’s logarithm is the exponent to which another fixed number (the base) must be raised to produce that number.

logic: the process of chaining concepts together–from a premise to a conclusion (inference)–in a way that the linkages may be agreeable (especially to others, else socially considered illogic).

“Logic is invincible because in order to combat logic it is necessary to use logic.” ~ French mathematician Pierre Boutroux

logogram: a symbol representing a word or its portion.

logos: Heraclitus’ term for Ĉonsciousness. See Tao.

logical positivism: see neopositivism.

lone pair: an electron pair not shared with other atoms.

long call: a loud, long call of orangutans that may carry for a kilometer, used for mating and other purposes.

long con: a grift that takes time to come to fruition.

longclaw: a small, ground-dwelling, insectivorous, African passerine in the Macronyx genus. Compare meadowlark.

longitudinal wave (aka compression wave): a wave in which displacement is in the same or opposite direction as wave propagation. Contrast transverse wave.

longwing (aka heliconian): a colorful butterfly in the Heliconius genus, distributed throughout the tropics and subtropics of the New World, as far north as the southern United States.

looking-glass self: the idea that self-identity grows from interpersonal interactions and the perceptions of others; coined by Charles Cooley.

loom: a device to weave cloth.

loon (aka diver (in the UK & Ireland)): a group of aquatic carnivorous bird endemic to North America and northern Eurasia.

loop quantum gravity: a quantum theory that quantizes all geometry, including space and gravity. Loop quantum gravity attempts to reconcile quantum mechanics with relativity.

Lorentz symmetry: the idea that all physical laws are the same for all observers; named after Hendrik Lorentz.

loris: a slow-moving, nocturnal, tailless, arboreal strepsirrhine, endemic to India, Sri Lanka, and parts of Southeast Asia.

lotus (sacred) (aka Indian lotus, Nelumbo nucifera): a flowering perennial aquatic plant, of which there are 2 species. The lotus is often wrongly considered a water lily. The lotus has been a symbol of divinity in Asian culture since antiquity, representing purity and enlightenment.

lotus effect: water-based self-cleaning of a waxed leaf owing to hydrophobic nanoscale structures in the wax on the leaf.

love: adoration of a concept.

lovebird: a small parrot with a big heart; 9 species, endemic to Africa and Madagascar.

Low Countries: the coastal region of northwestern Europe, where much of the land is below sea level. The Low Countries comprised Belgium, the Netherlands, and Luxembourg.

low-density lipoprotein (LDL): one of 5 groups of lipoproteins. LDL enables transportation of lipids – such as cholesterol – in extracellular fluid. Nutritionists generally advise limiting ingestion of foods high in LDL.

LSD (C33H35N5O5; lysergic acid diethylamide): a synthetic psychedelic derived from ergot fungus.

Lucasfilm (1971–2012): American film and TV show production company founded by George Lucas and sold to Disney in 2012.

luciferin: a bioluminescent compound.

Luddites: a 19th-century group of English textile artisans who took to destroying weaving machinery to protest capitalist exploitation, not technological progress per se, as is commonly portrayed.

lumbar vertebrae: the 5 vertebrae between the rib cage and the pelvis.

lunar cycle: the periodicity of the Moon’s orbit about Earth.

lunar mare: a large dark basaltic plain on the Moon, formed by ancient volcanic eruptions.

lung: the essential respiration organ in air-breathing animals.

lungfish (aka salamanderfish): a freshwater fish that can breathe air.

Lusitanian toadfish (Halobatrachus didactylus): a toadfish resident along the Atlantic and Mediterranean coasts of western Europe and western Africa. The Lusitanian toadfish has venomous spines.

lust: intense carnal desire.

Luzon: a northern island of the Philippines, the largest.

lupin (aka lupine): a legume in the Lupinus genus, found in the Americas, North Africa, and the Mediterranean.

lutung (aka langur, leaf monkey, Trachypithecus): an Asian monkey with a slim build and long tail.

lycopene: a bright red carotenoid found in tomatoes and other red fruits and vegetables.

Lydia: an Iron Age kingdom in western Anatolia that reached its apex in the 7th century BCE.

Lyme disease: an infectious disease caused by the pathogenic bacteria Borrelia burgdorferi, which are carried by Ixodes ticks. A rash that looks like a bull’s eye is an early symptom. Left untreated, the disease can debilitate the joints, heart, and central nervous system.

lymph: the animal bodily fluid that circulates through the lymphatic system, transporting cell nutrients (oxygen, moisture, food, hormones) and metabolic wastes.

lymph node: an oval organ that filters and traps foreign particles; part of the immune system.

lymphatic system: the part of the circulatory system carrying lymph.

lymphocyte: a type of white blood. There are 3 different lymphocytes: NK (natural killer) cells, T cells and B cells.

lyonization (aka X inactivation): the process in which 1 of 2 copies of the X chromosome in female mammals is inactivated.

lyse: to destroy a cell via lysins.

lysigeny (botany): the process of selectively eliminating cells to produce spaces for gas pathways; employed by plants to cope with waterlogging.

lysin (aka endolysin or murein hydrolase): an enzyme that cleaves a cell wall.

lysine acetylation: an epigenetic mechanism that affects histones by introducing an acetyl functional group.

lysis: viral reproductive release by cell wall rupture: killing the host cell in a violent outburst that releases a multitude of offspring. Contrast lysogeny.

lymph: the clear interstitial (extracellular) fluid that surrounds cells in vertebrates.

lymph node (aka lymph gland): an organ that filters and distributes lymph.

lymphatic system: a vertebrate circulatory system for lymph. The lymphatic system helps maintain fluid balance and assists in bodily defense (immune system).

lymphocyte: a type of white blood cell in the vertebrate adaptive immune system. The innate immune system operates through genetically programmed responses. In contrast, the adaptive immune system remembers past foes, to better dispatch nefarious invaders upon arrival.

lysogeny: a virus integrating itself into its host cell and replicating with the cell, secreting progeny viruses. Contrast lysis.

lysosome: the membrane-bound organelle in animal cells responsible for autophagy.