All articles starting with U
6,146 articles
Ultralight trike
An ultralight trike, also called a weight-shift control aircraft, is a powered aircraft with a hang-glider-style wing on a wheeled carriage, steered by shifting weight.
Ultraluminous X-ray source
An ultraluminous X-ray source (ULX) is an X-ray source outside a galaxy's nucleus that exceeds the Eddington limit for a stellar-mass black hole, usually through super-Eddington accretion.
Ultramagnetic MCs
Ultramagnetic MCs (Ultramagnetic MC's), Bronx hip-hop group formed 1984 with Kool Keith, Ced Gee, Moe Love, TR Love; debut Critical Beatdown (1988); credited as first rap group to use a sampler as an instrument.
Ultraman (ウルトラマン)
Ultraman (ウルトラマン) is a Japanese tokusatsu giant-hero franchise begun by Tsuburaya Productions in 1966 with Ultra Q and Ultraman; known for the 40-meter silver-and-red hero from Nebula M78, a Guinness-record series count, and its 60th anniversary in 2026.
Ultraman (ウルトラマン) (character)
Ultraman (ウルトラマン), the 1966 Tsuburaya Productions hero of light from Nebula M78, merged with SSSP member Hayata, stands 40 m, weighs 35,000 t, and fires the Spacium Beam, spawning a 60-year Ultra series franchise broadcast in over 100 countries.
Ultraman (ウルトラマン) (manga)
Ultraman (ウルトラマン) is a 2011 manga by Eiichi Shimizu and Tomohiro Shimoguchi, a human-sized power-suit sequel to the 1966 Ultraman series following Shinjiro Hayata; over 4 million copies, adapted into a Netflix 3DCG anime.
Ultraman Omega (ウルトラマンオメガ)
Ultraman Omega (ウルトラマンオメガ) is Tsuburaya's 2025 tokusatsu TV series: an amnesiac alien, Sorato, on a kaiju-free Earth transforms with the Omega Slugger; 25 episodes on TV Tokyo, July 2025 to January 2026, directed by Masayoshi Takesue.
Ultraman Orb (ウルトラマンオーブ)
Ultraman Orb (ウルトラマンオーブ) is Tsuburaya's 2016 tokusatsu series, the 42nd Ultraman, airing 25 episodes on TV Tokyo from July 9, 2016. Hero Gai Kurenai (Hideo Ishiguro) uses Fusion Up, combining two past Ultra warriors' powers via the Orb Ring, directed by Kiyotaka Taguchi for the franchise's 50th anniversary.
Ultraman Teo
Ultraman Teo (ウルトラマンテオ) is Tsuburaya Productions' 2026 tokusatsu TV series marking the Ultraman franchise's 60th anniversary. It follows alien refugee Ibuki Mitsuishi, a veterinary student from Planet H12 who reluctantly transforms into the blue giant Ultraman Teo via the Teo Crystar, airing Saturdays on TV Tokyo with worldwide streaming.
Ultraman: Rising (ウルトラマン：ライジング)
Ultraman: Rising (ウルトラマン：ライジング) is a 2024 Netflix CG animated film by Shannon Tindle and John Aoshima, made with ILM, in which baseball star Ken Sato raises a baby kaiju named Emi.
Ultramarathon
Ultramarathon (ultrarunning): any footrace longer than the 42.195 km marathon, from 50 km to 100 miles and beyond; governed internationally by the IAU under World Athletics, with Comrades as the oldest event.
Ultramarine
Ultramarine, also known as ultramarine blue, is a deep blue pigment historically made from lapis lazuli from Afghanistan and prized in Renaissance painting above all for the Virgin Mary's robes.
Ultramega OK
Ultramega OK is Soundgarden's 1988 debut full-length album, their only release on SST Records, nominated for a 1990 Grammy for Best Metal Performance and remixed by Jack Endino for a 2017 Sub Pop reissue.
Ultramen
Ultramen is a Brazilian rock band formed in 1991 in Porto Alegre, known for mixing rap with heavy guitars and later reggae, funk, and samba-rock.
Ultrametric space
An ultrametric space is a metric space in which the triangle inequality is replaced by the stronger ultrametric inequality; its basic example is the p-adic metric on the rationals.
Ultramicroelectrode
An ultramicroelectrode (UME) is an electrode with at least one dimension below 100 micrometers, where radial diffusion yields steady-state currents; it is used in scanning electrochemical microscopy and for detecting neurotransmitters in living tissue.
Ultramicroscopy
Ultramicroscopy: an Elsevier journal (ISSN 0304-3991, founded 1975) on microscopy instrumentation and theory, and separately a light-sheet technique imaging cleared centimeter-sized specimens like mouse brains at micrometer resolution.
Ultramicrotomy
Ultramicrotomy is the preparation of ultrathin sections, roughly 10 to 100 nm thick, using an ultramicrotome with a glass or diamond knife, the standard specimen method for transmission electron microscopy.
Ultramontanism
Ultramontanism, whose adherents are called Ultramontanes, is the tendency within Roman Catholicism emphasizing papal authority, which shaped the definitions of papal primacy and infallibility at Vatican I in 1870.
Ultrananocrystalline diamond
Ultrananocrystalline diamond (UNCD) is a thin-film diamond material with 2–5 nm grains, grown by chemical vapor deposition and developed at Argonne National Laboratory in the 1990s.
Ultranationalism
Ultranationalism: extreme, exclusionary nationalism; also called ultra-nationalism. A far-right ideology marked by hostility toward other nations, central to fascism (Griffin's palingenetic ultranationalism), and distinct from civic nationalism.
Ultranationalism (超国家主義) (Japan)
Ultranationalism (超国家主義, chōkokkashugi): Japan's radicalized state nationalism from the 1930s, centered on the emperor, Hakkō ichiū, State Shinto, and Asian aggression, dismantled by GHQ after 1945.
Ultranet (HVDC transmission project)
Ultranet is a 2,000-megawatt high-voltage direct current transmission line under construction in Germany, running about 340 kilometers from Osterath to Philippsburg, due operational at the end of 2026.
Ultrapar Participacoes
Ultrapar Participações S.A. is a Brazilian holding company focused on energy, mobility, and logistics, operating through Ipiranga fuel distribution, Ultragaz, Ultracargo, and Hidrovias, with origins in the 1937 founding of Ultragaz.
Ultrapower
An ultrapower is a model-theoretic construction building a new structure from many copies of one structure using an ultrafilter, the special case of an ultraproduct behind nonstandard analysis.
Ultraproduct
An ultraproduct is a model theory construction combining an infinite family of mathematical structures into one via an ultrafilter, preserving first-order properties by Łoś's theorem, defined by Jerzy Łoś in 1955.
Ultrapure water
Ultrapure water (UPW), known in labs as Milli-Q water, is water purified to remove ions, organics, particles, gases, and bacteria, defined by resistivity of 18.2 MΩ·cm and used mainly in semiconductor fabrication.
Ultras
Ultras: organised, choreographed football supporter groups originating in Italy (Fossa dei Leoni, AC Milan, 1968), with formal membership, capo-led chants, tifo displays, and pyrotechnics; distinct from hooligan firms, now global across 36 countries.
Ultrasensitive SERS detection
Ultrasensitive SERS detection is an analytical method that identifies molecules at extremely low concentrations, down to single-molecule events, by amplifying their Raman scattering on nanostructured metal surfaces.
Ultrashort echo time imaging
Ultrashort echo time (UTE) imaging is a magnetic resonance imaging technique that captures signal within tens of microseconds, making short-T2 tissues like cortical bone, tendons, and lung visible on MRI.