All articles starting with O
9,097 articles
Oath of Allegiance (Canada)
The Canadian Oath of Allegiance, chiefly the Oath of Citizenship in the Citizenship Act schedule, requires candidates 14+ to swear allegiance to the Crown; a 2021 amendment (Bill C-8, TRC Call 94) added the Constitution's Aboriginal and treaty rights clause.
Oath of Allegiance (United States)
The U.S. naturalization Oath of Allegiance (INA § 337, 8 U.S.C. § 1448; text at 8 CFR 337.1): mandatory public-ceremony oath renouncing foreign allegiance, supporting the Constitution, and committing to military or civilian service, with religious modifications and disability waivers.
Oath of office
Oath of office: a formal promise by incoming public officials to discharge duties faithfully and support the constitution. Covers the US Article VI and presidential oaths, 5 USC 3331, judicial oaths, and foreign variants.
Oath of office of the president of the United States
The oath of office of the president of the United States, fixed verbatim in Article II, Section 1, Clause 8, binds the president to faithfully execute the office and preserve, protect and defend the Constitution; "so help me God" and the Bible are tradition only.
Oath of the Horatii
Oath of the Horatii (Le Serment des Horaces) is Jacques-Louis David's 1784-85 Neoclassical oil painting in the Louvre, a royal commission showing three Roman brothers swearing an oath to fight the Curiatii of Alba.
Oathbreaker (band)
Oathbreaker is a Belgian extreme metal band from Ghent, formed in 2008 and fronted by vocalist Caro Tanghe, best known for the 2016 album Rheia.
Oathbreaker (Game of Thrones)
"Oathbreaker" is episode 3 of Game of Thrones season 6 (53rd overall), aired May 8, 2016; written by Benioff and Weiss, directed by Daniel Sackheim; covers Jon Snow's resurrection, his execution of the mutineers, and Bran's Tower of Joy flashback.
Oathbringer
Oathbringer is Brandon Sanderson's 2017 epic fantasy novel, Book Three of the Stormlight Archive, following Dalinar Kholin during a new Desolation on Roshar; a #1 New York Times bestseller and Audible's most pre-ordered book.
Oathkeeper
Oathkeeper: Game of Thrones season 4 episode 4 (April 27, 2014), written by Bryan Cogman, directed by Michelle MacLaren; also the Valyrian steel sword Jaime gives Brienne, reforged from Ice, and a Star Wars: Andor role.
Oaths of Strasbourg
The Oaths of Strasbourg (Serments de Strasbourg, Sacramenta Strasburgi) are mutual alliance oaths sworn 14 February 842 by Charles the Bald and Louis the German against Lothair I, preserved in Nithard's Historia and containing the earliest surviving extended Old French and Old High German texts.
Oatman, Arizona
Oatman, Arizona, a former gold-mining boomtown in the Black Mountains of Mohave County on Historic Route 66, once home to 10,000 people and over 1.8 million ounces of gold, now a living ghost town of about 100 residents famous for wild burros and Sitgreaves Pass.
Oatmeal
Oatmeal: ground, steel-cut, or rolled hulled oats (Avena sativa groats) and the porridge made from them. Types differ in processing, cooking time, and glycemic index; beta-glucan fiber supports its heart-health claims.
Oats Studios
Oats Studios is a Vancouver-area experimental film studio founded in 2015 by Neill and Mike Blomkamp, known for the free YouTube shorts Rakka, Firebase, and Zygote, Steam asset releases, and the 2021 Netflix anthology Volume 1.
Oatv
OATV, or O'Reilly AlphaTech Ventures, is a seed and early-stage venture capital firm founded in California in 2005 by Bryce Roberts, Mark Jacobsen, and Tim O'Reilly, affiliated with O'Reilly Media.
OAuth
OAuth, or Open Authorization, is an open standard for delegated authorization published by the IETF, with version 1.0 standardized in 2010 and OAuth 2.0 in 2012.
OAuth 2.0
OAuth 2.0 is an IETF authorization framework, standardized in RFC 6749 in 2012, that lets third-party applications obtain limited access to an HTTP service without user credentials.
Oaxaca
Oaxaca, a southern Mexican state (capital Oaxaca de Juárez), is among Mexico's most biodiverse and culturally rich entities, with over 10,200 recorded species and 16 ethnolinguistic groups, yet persistent poverty and a largely agricultural, informal economy.
Oaxaca cheese
Oaxaca cheese, or quesillo, is a Mexican pasta filata (stretched-curd) cow's-milk cheese from Reyes Etla, Oaxaca, with fibrous string texture, mild acid flavor, and excellent melting; protected as Quesillo de Reyes Etla since 2025.
Oaxaca City
Oaxaca City (Oaxaca de Juárez), capital of Oaxaca state, Mexico; founded 1529 as Antequera on a colonial grid plan; UNESCO World Heritage with Monte Albán since 1987; 270,955 residents (2020); major tourism economy.
Oaxaca–Blinder decomposition
The Oaxaca–Blinder decomposition is a statistical method that splits the mean difference between two groups, such as a wage gap, into explained and unexplained parts, introduced in 1973.
Oaz Nir
Oaz Nir is a quantitative researcher who was a partner and algorithm developer at Hudson River Trading for about fifteen years, helping lead its medium frequency trading push.
Ob
Ob (Обь): west Siberian river and FEOW freshwater ecoregion 602 (Polar freshwaters) in Kazakhstan and Russia; Ob-Irtysh basin 2,975,000 km2, 417 km3/year discharge, ~15% of Arctic Ocean river input.
Ob (鄂畢河, rivers_lake_centerlines:24)
The Ob (Обь; 鄂畢河) is a major west Siberian river formed by the Biya and Katun near Biysk, flowing north to the Gulf of Ob; third largest Arctic river by discharge, chief tributary the Irtysh.
OB association
An OB association is a loose grouping of young O- and B-type stars, defined by Viktor Ambartsumian in 1947, that disperses within tens of millions of years.
Ob-La-Di, Ob-La-Da
Ob-La-Di, Ob-La-Da: Beatles song by Paul McCartney, ska-styled, from the 1968 White Album; title from Nigerian conga player Jimmy Scott's phrase; 42-hour Abbey Road sessions; Marmalade's cover hit UK number one.
Oba Chandler
Oba Chandler (1946-2011), American murderer executed in Florida in 2011 for the 1989 Tampa Bay killings of tourists Joan, Michelle, and Christe Rogers; identified via handwriting billboards, distinct from other Chandlers.
Oba Femi
Oba Femi (Isaac Odugbesan, born 1998, Lagos) is a Nigerian WWE powerhouse wrestler on Raw, "The Ruler", a two-time NXT Champion, 2026 King of the Ring winner, and Brock Lesnar's conqueror at WrestleMania 42 and SummerSlam 2026.
Ōba Kagechika
Ōba Kagechika (大庭景親), also known as Ōba Saburō, was a late Heian warrior of Sagami Province, Japan, who crushed Minamoto no Yoritomo's first rising at Ishibashiyama in 1180 and was executed later that year.
Oba of Benin
Oba of Benin (Omo N'Oba N'Edo Uku Akpolokpolo): traditional monarch of the Benin Kingdom in Edo State, Nigeria, distinct from the Republic of Benin. Current holder Ewuare II, 40th Oba since 2016; dynasty dates to the 13th century; 1897 British conquest led to exile of Ovonramwen and looting of the Benin Bronzes.
Oba of Lagos
The Oba of Lagos is the traditional monarch of Lagos, Nigeria, heading a dynasty of Benin origin that dates to around 1600 and now serves a ceremonial role.