uakari: a bald-headed, short-tailed monkey of 4 species in the Cacajao genus, endemic to the Amazonian rainforest.
Uber (2009–): American multinational online transportation network company matching riders with contracted drivers.
Übermensch (aka overman, superman): Friedrich Nietzsche’s notion of superior people as admirable and worthy of emulation. Aside from elitist sentiment, Nietzsche was unclear exactly what he meant by Übermensch, other than being resolutely reality-based, in contrast to the otherworldliness that Christianity inspires.
ubit (universal quantum bit): an essential adjunct to the real-vector-space quantum model proposed by William Wootters.
Uganda: a country in east central Africa, to the north of Lake Victoria.
Uganda ironwood (Cynometra alexandri): a legume tree endemic to tropical lowland forests in central and east Asia. These trees may reach 46 meters in height.
ultimate attribution error: a group-level attribution error (bias).
ultrarelativistic: very close to the speed of light.
ultrasonic: a sound frequency above human hearing (20 kHz).
ultraviolet: the 10–400 nm band of the electromagnetic spectrum, shorter than visible light but longer than X-rays.
ultraviolet catastrophe: a late 19th-century classical-physics prediction contravened by black-body radiation. Classical physics predicts that a black body in thermal equilibrium will emit energy equally across all wavelengths (which it does not) and emit more energy as radiation frequency upon it increases, to infinity (which contradicts the thermodynamic law of the conservation of energy).
ultraviolet radiation (UVR): electromagnetic radiation at a wavelength between 10–400 nanometers.
umami (aka savory): one of the 7 basic human tastes (along with sweet, starch, sour, salty, fat, and bitter), activated by the amino acid glutamate.
unbroken supersymmetry: a variant of supersymmetry wherein each fermion flavor has a boson shadow and vice versa.
uncertainty principle: the principle that subatomic quanta are inherently probabilistic in their activity: a measurement may yield only an approximation of either a quantum’s position or its momentum, but not both simultaneously; an intrinsic property of Nature, not a measurement incapacity; proposed by Werner Heisenberg in 1926 and controversial ever since.
unconscious: autonomic mental processes which are not conscious; synonymous with subconscious. The term unconscious was coined by Friedrich Schelling in 1800. Sigmund Freud’s more circumscribed definition considered the unconscious partitioned from the conscious mind, and so not available for introspection, even as it influences behavior. Freud’s unconscious included thoughts, memory, affect, and motivation. Freud’s hypothesis of such an unconscious is unsupported. Compare conscious, subconscious, preconscious.
unconstrained cognition: perceptions which exceed normal sensory experience.
under-controlled aggressor: an often-violent person with weak internal controls against aggression; typically, prone to overreactive aggression. Contrast over-controlled aggressor.
underclass: the lowest social stratum in a society, usually comprising disadvantaged minority groups. Compare overclass.
understand: to develop a sense of contextual meaning.
understory: an underlying layer of vegetation; the vegetative layer between forest ground cover and the forest canopy. Compare overstory.
undulipodium (plural: undulipodia): a filamentous, motile, extracellular projection from a eukaryotic cell. See cilium, flagellum.
ungulate: a group of mammals which use the tips of their toes, typically hoofed, to sustain body weight while moving. Ungulates include the horse, cattle, bison, camel, goat, pig, sheep, donkey, deer, tapir, antelope, gazelle, giraffe, camel, rhino, and hippo. Even-toed ungulates (Artiodactyla) bear their weight equally between the 3rd and 4th toes. Odd-toed ungulates (Perissodactyla), which have an odd number of toes on their rear feet, bear weight on their 3rd toe.
unicameral: a legislative assembly with a single chamber. Contrast bicameral.
UNICEF (United Nations Children’s Emergency Fund) (1947–): a United Nations humanitarian program.
uniformitarianism: a hypothesis by James Hutton of steady-state existence: the same processes and natural laws that operate in the universe now have been constant everywhere since time immortal: “the present is the key to the past.” In a temporal asymmetry, from a saner historical perspective, understanding the past explains the present. Contrast catastrophism.
United Kingdom (UK; aka Britain): a European island nation, northwest of the continental mainland, comprising the 4 countries in the British Isles: England, Scotland, Wales, and Northern Ireland; sans Ireland, which is a separate nation. The UK is a constitutional monarchy with a parliamentary universal: including all without limit or exception.
United Nations (1945–): an intergovernmental organization promoting international cooperation. The UN replaced the ineffective League of Nations, which the United States refused to join (hence the League’s ineffectiveness).
United Netherlands (aka Dutch Republic, United Provinces ) (1581–1795): a historic republic where the present-day Netherlands is.
United States (US; aka America): the 3rd-largest country (9.6 million km2), just slightly larger than China, with 326 million people (2018). The US has the world’s-largest national economy, and is the planet’s greatest polluter, though China has been doing its best to catch up.
univalent (aka monovalent) (chemistry): have a valence of 1.
universal: including all without limit or exception.
universal common ancestor: the notion that life arose from a single life form.
universal law (physics): a proven axiom about a relationship between matter and energy.
universal mind: the idea of showtivity via a unified field of mentation; a synonym for coherence.
universe (aka cosmos): a presumed self-contained repository of energy – a characterization for which there is no evidence, and which quantum theory disclaims. This universe has ~4 trillion galaxies – half are light (with visible stars), half dark.
UNIX: an operating system developed by AT&T in the early 1970s.
unsaturated fat: a molecule of fat with 1 or more double bonds between carbon atoms. A fat molecule with only 1 double bond is monounsaturated. Molecules of fat with more than 1 double bond are polyunsaturated. Contrast saturated fat.
Upanishads (aka Vedānta) (from the 7th century BCE): a collection of ~200 texts which contain philosophic concepts central to Hinduism.
uracil (U) (C4H4N2O2): a nucleobase of RNA. Uracil is complementary to adenine. In DNA, uracil is replaced by thymine.
uranium (U): the element with atomic number 92; a silvery-white metal that is weakly radioactive because all its isotopes are unstable. The decay of uranium, thorium, and postassium-40 are a main source of heat in Earth’s mantle.
Uranus: the 7th planet from the Sun, and the lightest.
urea (CO(NH2)2 aka carbamide): a colorless, odorless, highly soluble, organic solid, crucial for animals to metabolize nitrogen-containing substances.
urogenital system (aka genitourinary system): the animal organ system including reproductive organs and the urinary system.
U.S. News & World Report (1948–): American media company publishing news, opinion, and consumer information. United States News (1933–) and World Report (1946–), both by conservative newspaperman David Lawrence, were merged to become U.S. News & World Report.
USB (Universal Serial Bus): a protocol specification for serial data transfer, developed in the mid-1990s.
USDA (United States Department of Agriculture) (1862–): the US federal agriculture agency.
user (computer): someone who uses software applications.
usufruct: the right of enjoying something without destroying or degrading it.
usury: lending at an exorbitant interest rate.
Utahraptor: a genus of theropods native to North America.
utilitarian organization: an organization people join to get paid. Compare normative organization, coercive organization.
utilitarianism: a normative ethics theory, that right action is the one that maximizes utility – either in bringing happiness or reducing suffering. According to utilitarianism, the moral worth of an act is solely determined by its outcome. Utilitarianism is essentially statistical hedonism. Contrast moral absolutism.
utility: fitness for some purpose.
utility (economics, psychology): satisfaction; usefulness.
utility theory (economics) (aka expected utility theory): the idea that the utility of an object or event derives from the satisfaction of its consumption. Utility theory was pioneered by John von Neumann and Oskar Morgenstern in 1944. See utility, consume.
utopian socialism: early, idealistic visions of socialism, as exemplified by Henri de Saint-Simon and Robert Owen. Contrast scientific socialism.