All articles starting with O
9,097 articles
Opobo–Bonny palm oil trade
The Opobo–Bonny palm oil trade was the nineteenth-century Niger Delta commerce in palm oil that replaced the slave trade, controlled by African middlemen until King Jaja's deposition in 1887.
Opoku Frefre
Opoku Frefre (c. 1760–1826) was the Gyasehene, royal treasurer of the Asante Empire for roughly a quarter century, and a leading general who signed the Anglo-Asante Treaty of 1817.
Opoku Ware I
Opoku Ware I was Asantehene, ruler of the Asante Empire, from about 1720 until his death in 1750, succeeding founder Osei Tutu and directing most of the empire's conquests.
Opole power station
The Opole power station (Elektrownia Opole) is a hard coal-fired power station near Opole, Poland, operated by PGE with about 3,300 MW of capacity, among the largest coal plants in Poland.
Opole Voivodeship
Opole Voivodeship (województwo opolskie) is Poland's smallest province by population, created 1 January 1999 with capital Opole; 923.5 thousand residents, industrial-agricultural economy, highest per-capita GHG emissions in Poland.
Opon Ifa
Opon Ifa (ọpọ́n Ifá) is the carved wooden tray on which a Yoruba diviner marks the figures of Ifá divination in powder, its rim bearing the face of Eshu.
Opone
Opone (Greek Ὀπώνη), also called Oponi, was an ancient market-town on the northern Somali coast, usually identified with the Hafun peninsula and described in the Periplus of the Erythraean Sea.
Opontia
Opontia was a Dubai-based e-commerce brand aggregator founded in 2021 by Philip Johnston and Manfred Meyer, acquiring brands across the Middle East, Africa, and Eastern Europe.
Oportuzumab monatox
Oportuzumab monatox (Vicinium, Vicineum, VB4-845) is an investigational anti-EpCAM scFv fused to Pseudomonas exotoxin A, given intravesically for BCG-unresponsive bladder cancer; FDA CRL and EMA withdrawal in 2021.
Opossum
Opossums are New World marsupials making up the family Didelphidae and the order Didelphimorphia, with over 135 species from Patagonia to northern North America, including the Virginia opossum.
Oppam (ഒപ്പം)
Oppam (ഒപ്പം) is a 2016 Indian Malayalam crime thriller directed by Priyadarshan, starring Mohanlal as a blind lift operator who witnesses a murder; it became an Onam box-office success.
Oppau explosion
The Oppau explosion, also called the Oppau disaster, destroyed much of the German town of Oppau on 21 September 1921, when blasting at a BASF fertilizer silo killed more than 500 people.
Oppegård
Oppegård was a municipality in Akershus, Norway (municipality number 0217), created in 1915 from Nesodden, with center Kolbotn; merged with Ski on 1 January 2020 to form Nordre Follo.
Oppein Home Group
Oppein Home Group (欧派家居) is a Guangzhou-based Chinese maker of customized home furnishings, founded by Yao Liangsong in 1994 and listed on the Shanghai Stock Exchange since 2017.
Oppelia
Oppelia is an extinct ammonite genus in the family Oppeliidae (Haploceratoidea), living from the Middle Jurassic to Early Cretaceous (about 172–136 Ma), with subgenera Oecotraustes, Oppelia, and Trimarginites; not the mite genus Oppiella.
Oppenauer oxidation
The Oppenauer oxidation is the aluminum alkoxide-catalyzed oxidation of secondary alcohols to ketones using excess acetone, reported by R. V. Oppenauer in 1937 and long central to steroid chemistry.
Oppenheimer (film)
Oppenheimer (2023) is Christopher Nolan's Universal Pictures biographical drama about J. Robert Oppenheimer and the Manhattan Project, based on American Prometheus, starring Cillian Murphy; it won seven Oscars including Best Picture and grossed over a billion dollars.
Oppenheimer (lunar crater)
Oppenheimer is a 201-km-wide floor-fractured impact crater on the lunar far side at 35.3°S, 166°W in the South Pole–Aitken basin, named for physicist J. Robert Oppenheimer (IAU 1970), with Vulcanian pyroclastic deposits on its floor.
Oppenheimer family
The Oppenheimer family is a South African business dynasty of German-Jewish origin that founded Anglo American in 1917 and controlled De Beers until selling its stake in 2012.
Oppenheimer pole
An Oppenheimer pole is a galvanized iron telegraph pole of three telescoping tubes, patented by German-born engineer Joseph Oppenheimer in 1867 and used across Australia's Overland Telegraph Line.
Oppenheimer–Snyder collapse
The Oppenheimer–Snyder collapse is an exact solution of the Einstein field equations describing the gravitational collapse of a pressureless spherical star into a black hole, published in 1939.
Oppidum
Oppidum (plural oppida): Latin 'town' used by Caesar for Gallic centers, now the archaeological term for large Late Iron Age fortified settlements (at least 10 ha) across temperate Europe, from Bibracte to Manching, often low-density assembly and trade centers.
Oppidum des Caisses de Jean-Jean
Oppidum des Caisses de Jean-Jean, also Caisses de Saint-Jean: a 14-hectare fortified Iron Age and Roman-era settlement in the Alpilles at Mouriès, Bouches-du-Rhône, France, known for its thick multiple ramparts and horse-and-rider stelae.
Oppikoppi
Oppikoppi is a long-running South African music festival held on a farm near Northam, Limpopo, first staged in 1994 and known as the country's biggest rock festival.
Opplane
Opplane, Inc. is an enterprise software company in Santa Clara, California, founded by Mohan Trikha in 2018, building data modernization and governance products that help financial institutions deploy AI.
Opple Lighting
Opple Lighting (欧普照明) is a Chinese home and commercial lighting manufacturer founded in 1996 by the married couple Wang Yaohai and Ma Xiuhui, now headquartered in Shanghai and listed on the Shanghai Stock Exchange.
Oppo
Oppo, also known as OPPO Electronics, is a Chinese consumer electronics company founded in 2004 in Dongguan, Guangdong, and one of the world's largest smartphone makers.
Oppo Find X9
The Oppo Find X9 is an Android flagship smartphone released by OPPO in late 2025, with a Dimensity 9500 chip, 7025 mAh battery, and triple 50 MP Hasselblad cameras.
Opportunistic beamforming
Opportunistic beamforming is a multi-antenna wireless technique that varies antenna phases pseudorandomly and schedules users whose channels peak, introduced by Viswanath, Tse, and Laroia in 2002.
Opportunistic infection
Opportunistic infection (OI): infections more frequent or severe in immunocompromised people, especially with HIV, cancer, or transplants; examples include PCP, tuberculosis, toxoplasmosis, candidiasis, and CMV retinitis.