All articles starting with U
6,146 articles
Underdog (TV series)
Underdog (The Underdog Show) is a 1964-1967 American Saturday morning cartoon by Total Television for General Mills, about Shoeshine Boy, a rhyming superhero dog voiced by Wally Cox, later a 2007 film and new animated series.
Underfill
Underfill is a silica-filled epoxy that fills the gap between a flip-chip silicon die and its packaging substrate, redistributing thermomechanical stress to protect solder joints from thermal fatigue.
Underfill epoxy
Underfill epoxy is a silica-filled thermosetting polymer dispensed into the gap beneath a flip chip, mechanically coupling it to its substrate and protecting the solder bumps.
Undergraduate degree
Undergraduate degree: the first tertiary qualification, chiefly the bachelor's degree (ISCED level 6, UNESCO 'first university degree'). Distinguished from short-cycle tertiary and master's long first degrees; OECD data show 77% of first-time graduates earn one, with a 39% earnings premium.
Undergraduate education
Undergraduate education: pre-degree higher education, chiefly bachelor's (ISCED 6) and short-cycle (ISCED 5) programs. Covers international classification, curriculum history, completion rates, earnings premiums, and US enrollment and funding trends.
Underground (1995 film)
Underground (Podzemlje) is Emir Kusturica's 1995 Palme d'Or-winning epic black comedy about Marko and Blacky, Belgrade arms dealers kept underground for decades by a lie that World War II continues, spanning Yugoslavia's collapse; controversial as alleged Serbian propaganda.
Underground (music)
Underground, or el underground, was the early-1990s Puerto Rican mixtape and club scene where reggae en español and hip hop fused into the music that became reggaetón.
Underground (TV series)
Underground is an American historical drama series about the Underground Railroad, created by Misha Green and Joe Pokaski, which ran for two seasons on WGN America from 2016.
Underground (지하도) (2026 film)
Underground (지하도, Jihado) is a 2026 South Korean mystery horror thriller directed by Choi Woo-sik, starring Shin Hyun-soo and Lee Yu-ji, about spirits haunting a halted subway extension; released 13 August 2026 by EO Contents Group.
Underground Atlanta
Underground Atlanta, also called the City Beneath the Streets, is a historic downtown Atlanta entertainment district beneath 1920s viaducts; opened 1969, closed 1980, reopened 1989 for $142 million, sold to Lalani Ventures for $31 million in 2020.
Underground city
An underground city is a network of pedestrian walkways, shops, and transit connections built below street level downtown, letting people move without going outdoors; Montreal's RÉSO and Toronto's PATH are the best-known examples.
Underground City, Montreal
The Underground City of Montreal, officially known as RÉSO, is an indoor pedestrian network of about 32 km of tunnels linking shops, offices, hotels, and metro stations downtown.
Underground coal gasification
Underground coal gasification converts coal in place into synthesis gas by injecting an oxidant into a seam and igniting it, reaching coal too deep to mine.
Underground comix
Underground comix: self-published, countercultural American comic books of the 1960s–70s, also called underground comics, defying the Comics Code; launched by Robert Crumb's Zap Comix (1968), sold in head shops, spawning women's, queer, and alternative comics.
Underground comix publishers
Underground comix publishers were small, self-run comic companies of the late 1960s and 1970s, concentrated in the San Francisco Bay Area and Milwaukee, that produced uncensored countercultural comics.
Underground film
Underground film, or underground cinema, denotes films made outside the commercial mainstream, especially 1960s American experimental cinema (Mekas, Film-Makers' Cooperative, Flaming Creatures) and Britain's countercultural scene.
Underground forum
An underground forum is an online message board, on the open web or darknets, where cybercriminals share knowledge, trade stolen data and illicit tools, and advertise criminal services.
Underground gas storage
Underground gas storage is the practice of holding natural gas in depleted oil and gas reservoirs, aquifers, and salt caverns, so surplus gas injected in low-demand periods can be withdrawn at peak.
Underground irrigation canal
Underground irrigation canal, chiefly the Persian kārēz (کاریز) or qanat: a gravity-fed shaft-and-gallery aqueduct from Iran and Afghanistan irrigating about 1.5 million hectares, with regional names falaj, foggara, and karez.
Underground lake
Underground lake, also called cave lake or karst lake: standing water pooled in caves, mostly in karst terrain. Key facts include sump entrances, speleogenetic role, Škocjan Dead Lake, Devils Hole, and Yucatán flooded systems.
Underground living
Underground living: dwelling in excavated or earth-sheltered spaces, from China's 7000-year silo-cave pit courtyards and Iran's Shavadan to modern earth-bermed houses, valued for thermal stability but challenged by moisture, ventilation, and health concerns.
Underground mining (soft rock)
Underground mining of soft rock extracts coal and potash deposits from beneath the surface, using continuous cutting machines and two main method families, room-and-pillar and longwall mining.
Underground music
Underground music: music outside or opposed to mainstream popular culture, spanning noise, free improvisation, extreme metal, and independent hip-hop and dance scenes; defined by secrecy, counterculture, and DIY scene infrastructure.
Underground nuclear testing
Underground nuclear testing is the detonation of a nuclear explosive in a shaft or tunnel below ground, retaining most radioactive debris; more than 1,850 tests have been conducted.
Underground passages
Underground passages, Exeter: medieval stone-lined access tunnels and conduits in the city's water supply, dating from a 1226 conduit, scheduled monument NHLE 1003851 since 1935, partly open for guided tours.
Underground press
Underground press: independent, dissident publications outside state or mainstream channels, including Soviet-bloc samizdat, WWII resistance sheets, and 1960s countercultural papers like the Berkeley Barb, distinguished by clandestine production and censorship resistance.
Underground Railroad
The Underground Railroad was the clandestine network of safe houses, routes, and Black and white volunteers that helped tens of thousands of enslaved people escape to free states and Canada before the Civil War; Thomas Smallwood coined the name in 1842.
Underground Shrine (Paestum)
Underground Shrine (Sacello Ipogeico, Heroon of Paestum): a sealed ~510 BC stone chamber on the agora of Poseidonia-Paestum, Italy, holding bronze jars whose 2025 analysis confirmed honey, interpreted as a founder's cenotaph.
Undergrounding
Undergrounding is the practice of placing electric power lines below ground instead of on poles, improving reliability and reducing wildfire risk at much higher cost.
Underlay cognitive radio
Underlay cognitive radio is a spectrum-sharing approach, one of three classical cognitive radio paradigms, where secondary users transmit concurrently with licensed users while keeping interference below a threshold.