All articles starting with O
9,097 articles
Overtopping protection
Overtopping protection is the armoring of a dam, most often an earthen embankment, so floodwater flowing over its crest does not erode it and cause a breach.
Overtoun Bridge
Overtoun Bridge, called the dog suicide bridge, is a road bridge over the Overtoun Burn near Dumbarton, Scotland, known for reports of dogs falling from its parapet.
Overtreatment
Overtreatment is the excessive provision of medical treatment or preventive procedures, typically arising from overdiagnosis, and is a major component of medical overuse alongside it.
Overture
Overture: an orchestral introduction to an opera, oratorio, or ballet, or an independent one-movement concert piece. Key forms: Lully's French overture, Scarlatti's Italian overture, 19th-century concert overture.
Overture Walker
Overture Walker is an American Democratic politician elected to the South Carolina Senate from District 22 in 2024, after serving as a Richland County Councilman and Columbia Municipal Court judge.
Overturn
Overturn: in oceanography, the mixing of stratified water due to density instability, and the related global overturning circulation (thermohaline circulation, AMOC) that sinks dense polar water and redistributes heat, salt, and carbon worldwide.
Overturning in the Subpolar North Atlantic Program
The Overturning in the Subpolar North Atlantic Program (OSNAP) is an international program measuring the Atlantic meridional overturning circulation with a moored array since 2014.
Overvalued ideas
Overvalued ideas (Ueberwertige Idee), coined by Carl Wernicke in 1892, are ego-syntonic, emotionally amplified beliefs dominating behavior, less intense than delusions; ICD-11 code MB26.6, linked to anorexia, BDD, OCD, and forensic threat assessment.
Overview effect
The overview effect is a cognitive shift reported by astronauts viewing Earth from space, first named by Frank White, who explained it in his 1987 book.
Overview of gun laws by nation
Overview of gun laws by nation: how countries regulate civilian firearms. Civilians hold ~650 million guns; rules range from Japan's near-total ban to permissive US licensing, with most nations banning fully automatic weapons.
Overview of statistics and probability journals
Statistics and probability journals are the peer-reviewed periodicals where statistical theory, methods, and applications are published, led by titles like JASA, Biometrika, and the Annals of Statistics.
Overwatch
Overwatch is a team-based first-person shooter developed and operated by Blizzard Entertainment, in which two teams of heroes with distinct abilities fight over objectives, launched in 2016 and now free-to-play.
Overwatch (2016 TV series)
Overwatch (2016 TV series) is the TVDB catalog entry for Blizzard Entertainment's Overwatch animated shorts and hero trailers on YouTube, first aired November 7, 2014, averaging 6 minutes; no standalone Overwatch TV series exists, a 2020 Netflix adaptation having failed.
Overwatch (video game)
Overwatch (Overwatch 2 since October 2022): Blizzard's team-based hero shooter with tank, damage, and support roles, born from the cancelled $80M Project Titan, a $1B+ loot-box pioneer, city-franchise Overwatch League, and a 5v5 free-to-play battle-pass pivot.
Overwatch 2
Overwatch 2, also called Overwatch after February 2026, is Blizzard's free-to-play 5v5 hero shooter launched October 4, 2022, known for the Push mode, canceled PvE, and the Reign of Talon relaunch.
Overwatch and pornography
Overwatch and pornography: sexually explicit fan and studio material based on Blizzard's 2016 hero shooter Overwatch; Overwatch ranked 11th on Pornhub's 2016 searches, D.Va led 2017 character searches, and Blizzard issued takedowns including Playwatch.
Overwatch Champions Series
The Overwatch Champions Series (OWCS) is the premier esports circuit for Blizzard's hero shooter Overwatch, launched in 2024 as an open-competition replacement for the Overwatch League.
Overwatch League
Overwatch League (OWL), Activision Blizzard's city-franchised professional esports league for Overwatch, ran 2018-2023 with $20 million franchise slots, 20 teams, and was replaced by the Overwatch Champions Series in 2024.
Overwatch seasonal events
Overwatch seasonal events are Blizzard's limited-time holiday and themed celebrations in the hero shooter Overwatch (formerly Overwatch 2), running since the July 2016 Summer Games with modes like Lúcioball and Mei's Snowball Offensive, evolving from event loot boxes to a shop, battle pass, and 2026 faction meta events.
Overweight
Overweight: excess body weight relative to height, defined as BMI 25–29.9 in adults (WHO: ≥25). Affects 2.6 billion adults in 2024; raises risk of cardiovascular disease, diabetes, and cancers.
Overweight in adults
Overweight in adults: BMI 25–29.9 kg/m² (obesity ≥30) by WHO definition. 45% of adults (2.6 billion) were overweight in 2024, up from 25% in 1990; diagnosis now pairs BMI with waist measures.
Overwhelming post-splenectomy infection
Overwhelming post-splenectomy infection (OPSI), or post-splenectomy sepsis, is fulminant sepsis in asplenic or hyposplenic people, mainly from Streptococcus pneumoniae and other encapsulated bacteria, progressing within 24-48 hours with 50-70% mortality if untreated.
Overwintering
Overwintering: how organisms and historically humans survive winter, via migration, dormancy (diapause, brumation, hibernation), freeze tolerance or avoidance, energy storage, and perennating plant organs.
Oveta Culp Hobby
Oveta Culp Hobby (1905-1995), Texas journalist and civil servant, was first director of the Women's Army Corps in World War II and first Secretary of Health, Education, and Welfare (1953-1955) under Eisenhower.
Ovi
Ovi, born Ovidiu Cernăuțeanu, is a Romanian singer-songwriter and producer based in Norway who finished third at Eurovision 2010 with Paula Seling on "Playing with Fire".
Ovid
Ovid (Publius Ovidius Naso, 43 BCE–17 CE), Roman poet of the Amores, Heroides, Ars Amatoria, Metamorphoses, Fasti, and exile poetry (Tristia, Epistulae ex Ponto); banished by Augustus in 8 CE to Tomis, where he died; major influence on later European literature and art.
Ovid Densusianu
Ovid Densusianu (Ovid Densușianu) was a Romanian philologist, linguist, and poet, a professor at the University of Bucharest who founded the Bucharest linguistic school and promoted symbolism.
Ovid Therapeutics Inc.
Ovid Therapeutics Inc. is a New York-based, clinical-stage biopharmaceutical company founded in 2014 by Matthew During and Jeremy Levin that develops small-molecule medicines for rare epilepsies and other brain conditions.
Ovidio Guzmán López
Ovidio Guzmán López, alias El Ratón, son of El Chapo and alleged Chapitos leader of the Sinaloa Cartel; arrested in Culiacán 2019 and 2023, extradited to the US in 2023, pleaded guilty in 2025 and agreed to cooperate.
Ovídio Martins
Ovídio de Sousa Martins (1928–1999) was a Cape Verdean poet and journalist who wrote in Portuguese and Cape Verdean Creole, known for the anticolonial poem "Anti-evasão" (1962).