Search by letter: O
Search by letter
Search by letter: O
- Osvaldo Bayer: Argentine journalist, historian and human rights advocate Osvaldo Bayer
- Osvaldo Fattori — Italian footballer (1922–2017) Osvaldo Fattori
- Osvaldo Hurtado — Ecuadorian politician, writer and former president Osvaldo Hurtado
- Osvaldo Suárez — Argentine long-distance runner and coach Osvaldo Suárez
- Oswald (TV series)
- Oswald Avery — Pioneer Who Identified DNA as Genetic Material Oswald Avery
- Oswald Chambers — Evangelist and Author of My Utmost for His Highest Oswald Chambers
- Oswald Morris: British cinematographer and Academy Award winner Oswald Morris
- Oswald of Northumbria: king, Christian ruler, and saint Oswald of Northumbria
- Oswald the Lucky Rabbit
- Oswaldo de Oliveira — Brazilian football manager Oswaldo de Oliveira
- Oswaldo Larriva — Ecuadorian politician and academic Oswaldo Larriva
- Oswaldo López Arellano: Honduran military leader and two-time president Oswaldo López Arellano
- Oswaldo Sánchez — Mexican goalkeeper and club captain Oswaldo Sánchez
- Oswaldo Vigas: Venezuelan painter and muralist Oswaldo Vigas
- Oswego bass (regional common name for certain North American sunfish) Oswego bass
- Oswego County, New York
- Oswego, Illinois
- Oswego, Kansas
- Oswestry, Shropshire: Market Town on the English–Welsh Border Oswestry
- Oświęcim — town in southern Poland and site of the Auschwitz memorial Oświęcim
- Oswiu of Northumbria
- Ot en Sien: Dutch children's stories, education and cultural legacy Ot en Sien
- Ota Filip: Czech novelist, journalist and dissident Ota Filip
- Ōta, Tokyo (Ōta-ku) Ōta, Tokyo
- Otakar Brousek, Sr. — Czech stage, film and voice actor Otakar Brousek, Sr.
- Otakar Krámský (Czech hillclimb racing driver) Otakar Krámský
- Ōtaki, Chiba
- Otaku: definition, history, culture, and social perceptions Otaku
- Otar Patsatsia
- Otávio Frias Filho — Brazilian editor who led Folha de S.Paulo (1957–2018) Otávio Frias Filho
- Otelfingen
- Otello (Verdi) — Opera in Four Acts Otello
- Otelo Saraiva de Carvalho: Portuguese military strategist and revolutionary Otelo Saraiva de Carvalho
- Ōtemachi Station (Tokyo)
- Otero County, Colorado
- Otero County, New Mexico: geography, history, and key features Otero County, New Mexico
- Otfried Preußler
- Othallo Tabia — Indian professional football (soccer) player Othallo Tabia
- Othello — Shakespeare’s Tragedy of Jealousy and the Moor of Venice Othello
- Other Ocean Interactive — American video game developer and contract studio Other Ocean Interactive
- Other People's Money (1991 film) Other People's Money
- Othmarsingen — municipality in the district of Lenzburg, Canton Aargau Othmarsingen
- Othniel Charles Marsh
- Otho, Iowa
- Gerald Otieno Kajwang Otieno Kajwang
- Otis Clay: American Soul and R&B Singer Otis Clay
- Otis Redding — American soul singer and songwriter Otis Redding
- Otis Rush: West Side Chicago Blues Guitarist and Singer Otis Rush
- Otitis: ear inflammation — types, causes, symptoms, diagnosis, and treatment Otitis
- Otjozondjupa Region (Namibia) Otjozondjupa Region
- Otley, Suffolk (village and civil parish) Otley
- Otmar Gutmann — Creator of Pingu and Stop‑Motion Animator Otmar Gutmann
- Oto, Iowa — small city in the Sioux City metropolitan area Oto, Iowa
- Otoe (Jiwére): Midwestern Siouan people Otoe
- Otoe County, Nebraska
- Otogizōshi: Japanese illustrated short stories of the Muromachi period Otogizōshi
- Ōtoku: Japanese era (1084–1087) under Emperor Shirakawa Ōtoku
- Henri Coandă International Airport (Otopeni) Otopeni Airport
- Otoya Yamaguchi
- Otra Cosa — Julieta Venegas (2010 album) Otra Cosa
- Otrera — queen and matriarch of the Amazons Otrera
- Otsego County, Michigan
- Otsego County, New York
- Otsego Hall — ancestral home of James Fenimore Cooper Otsego Hall
- Otsego, Minnesota — city profile Otsego, Minnesota
- Ōtsu, Shiga — prefectural capital on Lake Biwa Ōtsu, Shiga
- Ottakring (16th District of Vienna) Ottakring
- Ottana: town and comune in central Sardinia Ottana
- Ottauquechee River
- Ottava rima
- Ottawa: Canada’s capital city, geography, history and cultural life Ottawa
- Ottawa County (United States) Ottawa County
- Ottawa County, Kansas standard abbreviation: OT
- Ottawa County, Michigan: overview, history, communities and features Ottawa County, Michigan
- Ottawa County, Ohio
- Ottawa County, Oklahoma
- Ottawa Lady Senators — women's ice hockey team Ottawa Lady Senators
- Ottawa Redblacks
- Ottawa River
- Ottawa Senators (NHL team) Ottawa Senators
- Ottawa Senators (original hockey club, 1883–1954) Ottawa Senators (original)
- Ottawa University: history, campuses, and academic profile Ottawa University
- Ottawa, Illinois — River city and county seat in north-central Illinois Ottawa, Illinois
- Ottawa, Kansas — county seat on the Marais des Cygnes River Ottawa, Kansas
- Ottawa, Minnesota
- Ottawa, Ohio — village and county seat of Putnam County Ottawa, Ohio
- Ottenbach, Affoltern District, Canton of Zurich, Switzerland Ottenbach, Switzerland
- Otter — aquatic mustelids: overview, behavior, habitat and conservation Otter
- Otter Tail County, Minnesota
- Ottery St Mary: historic market town and civil parish in East Devon Ottery St Mary
- Ottignies-Louvain-la-Neuve
- Otting: Municipality in Donau-Ries, Bavaria, Germany Otting
- Ottmar Hitzfeld: Career and legacy of a German football coach Ottmar Hitzfeld
- Ottmar Walter — German footballer (1924–2013) Ottmar Walter
- Ottmarsheim — commune in Haut-Rhin, Alsace Ottmarsheim
- Otto Arosemena: President of Ecuador (1966–1968) and Democratic Rebuilder Otto Arosemena
- Otto Carius: German World War II Tank Commander and Postwar Author Otto Carius
- Otto Fritz Meyerhof — pioneer of muscle metabolism and glycolysis Otto Fritz Meyerhof
- Otto Georg Thierack (1889–1946), Nazi jurist and Reich Minister of Justice Otto Georg Thierack
- Otto Grotewohl: East German statesman and first Prime Minister Otto Grotewohl
- Otto Hahn — German chemist and discoverer of nuclear fission Otto Hahn
- Otto Heinrich Warburg
- Otto I the Illustrious, Duke of Saxony (ca. 841–912) Otto I the Illustrious
- Otto Kerner Jr.: Illinois governor, Kerner Commission chair, and convict Otto Kerner Jr.
- Otto Klemperer (1885–1973) Otto Klemperer
- Otto Konrad (Austrian football goalkeeper and coach) Otto Konrad
- Otto Lilienthal: Pioneer of Gliding and Modern Aeronautics Otto Lilienthal
- Otto Loewi and the discovery of chemical nerve transmission Otto Loewi
- Otto Meißner
- Otto Neurath: philosopher, social scientist and pioneer of pictorial statistics Otto Neurath
- Otto Pérez Molina
- Otto Piene: German artist and cofounder of the ZERO movement Otto Piene
- Otto Preminger: Austrian-American Film and Theatre Director Otto Preminger
- Otto Rehhagel: German football coach and player, manager of Werder Bremen and Greece Otto Rehhagel
- Otto Sander: German stage and film actor noted for his deep voice Otto Sander
- Otto Schily — German interior minister and lawyer Otto Schily
- Otto Schubiger — Swiss ice hockey player (1925–2019) Otto Schubiger
- Otto Sonnenholzner: Ecuadorian broadcaster, economist and former vice president Otto Sonnenholzner
- Otto Struve (1897–1963): astronomer, observatory director and early SETI advocate Otto Struve
- Otto I (Otto the Great): King of the Germans and Holy Roman Emperor Otto the Great
- Otto von Bismarck — Prussian statesman and architect of German unification Otto von Bismarck
- Otto von Guericke: inventor of the vacuum pump and Magdeburg hemisphere experiments Otto von Guericke
- Otto von Habsburg (1912–2011): Last Crown Prince and European Statesman Otto von Habsburg
- Otto Wagner: Austrian Architect and Urban Planner Otto Wagner
- Otto Wanz: Austrian strongman, professional wrestler and promoter Otto Wanz
- Otto Warmbier — American student detained and repatriated from North Korea Otto Warmbier
- Otto Ziege — German Road Racing Cyclist (1926–2014) Otto Ziege
- Otto, Wyoming — Unincorporated community in Big Horn County Otto, Wyoming
- Ottobrunn (Bavaria) Ottobrunn
- Ottoman architecture: form, development, and cultural legacy Ottoman architecture
- Ottoman dynasty (House of Osman) Ottoman dynasty
- Ottoman Empire: history, structure, and legacy Ottoman Empire
- Ottoman Turkish (Lisân-ı Osmânî): language of Ottoman administration and literature Ottoman Turkish
- Ottonian dynasty (Liudolfing/Saxon rulers of early medieval Germany) Ottonian dynasty
- Ottosen, Iowa: small Midwestern city overview Ottosen, Iowa
- Ottumwa, Iowa: Overview, history, and local features Ottumwa, Iowa
- Ötzi the Iceman: Copper Age mummy of the Alps Ötzi the Iceman
- Ouachita County, Arkansas
- Ouachita Mountains
- Ouachita Parish, Louisiana
- Ouaddaï Prefecture (former administrative division of Chad) Ouaddaï (prefecture)
- Ouaddaï Region — eastern Chad Ouaddaï Region
- Ouagadougou — capital and largest city of Burkina Faso Ouagadougou
- Ouahigouya: regional capital and market city in northern Burkina Faso Ouahigouya
- Ouaka (prefecture of the Central African Republic) Ouaka
- Ouanaminthe (Wanament) — Haitian border city and market town Ouanaminthe
- Ouanne — commune in Yonne, Bourgogne-Franche-Comté, France Ouanne
- Ouargla Province (Wilaya of Ouargla, Algeria) Ouargla Province
- Ouch, Lower Dir (Khyber Pakhtunkhwa, Pakistan) Ouch, Lower Dir
- Oud: the fretless pear‑shaped lute of the Middle East Oud
- Oud-Heverlee: Municipality in Flemish Brabant, Belgium Oud-Heverlee
- Oud-Turnhout (municipality in Antwerp, Belgium) Oud-Turnhout
- Oude IJsselstreek
- Oudenaarde — historic town in East Flanders, Belgium Oudenaarde
- Oudenburg (Belgium) — municipality in West Flanders Oudenburg
- Ouder-Amstel — municipality in North Holland, Netherlands Ouder-Amstel
- Oudergem (Auderghem) — municipality in the Brussels-Capital Region Oudergem
- Oudewater — historic town and municipality in the Netherlands Oudewater
- Oudsbergen
- Ouémé Department, Benin Ouémé Department
- Ouest (department, Haiti) Ouest (department)
- Ouest Lausannois District (Canton of Vaud, Switzerland) Ouest Lausannois District
- Ouézy — Commune in Calvados, Normandy, France Ouézy
- Ouffet — Municipality in Liège Province, Belgium Ouffet
- Ouffières — small commune in Calvados, Normandy, France Ouffières
- Ouham (prefecture of the Central African Republic) Ouham
- Ouham-Pendé: Prefecture in the northwestern Central African Republic Ouham-Pendé
- Oui, oui, oui, oui — 1959 French pop song by Jean Philippe Oui, oui, oui, oui
- Ouida (Marie Louise de la Ramée) Ouida
- Ouija board: history, use, and scientific explanation Ouija board
- Ouillon: a rural commune in Pyrénées-Atlantiques, southwestern France Ouillon
- Ouilly-du-Houley, Calvados (Normandy) Ouilly-du-Houley
- Ouilly-le-Tesson — commune in Calvados, Normandy Ouilly-le-Tesson
- Ouilly-le-Vicomte: commune in Calvados, Normandy Ouilly-le-Vicomte
- Ouistreham: Normandy port, seaside resort and gateway to Caen Ouistreham
- Oulches-la-Vallée-Foulon
- Oulchy-la-Ville (Aisne, France) Oulchy-la-Ville
- Oulchy-le-Château
- Oulens-sous-Echallens — municipality in the Gros-de-Vaud, Canton of Vaud Oulens-sous-Echallens
- Oulens-sur-Lucens
- Oulmes (Vendée) — former commune in Pays de la Loire Oulmes
- Oulton Broad South railway station
- Oulu — city in Northern Ostrobothnia, Finland Oulu
- Oulujärvi — the Kainuu Sea (large lake in Finland) Oulujärvi
- Oum El Bouaghi Province — northeastern Algerian province overview Oum El Bouaghi Province
- Ounce (unit of mass and weight) Ounce
- Oupeye — Municipality in Liège Province, Wallonia, Belgium Oupeye
- Our (river)
- Our Band Could Be Your Life: Scenes from the American Indie Underground, 1981–1991 Our Band Could Be Your Life
- Our Dancing Daughters (1928) — MGM silent film and Jazz Age portrait Our Dancing Daughters
- Our Girl Friday (1953 British romantic comedy) Our Girl Friday
- Our Lady of Fátima Our Lady of Fatima
- Our Lady of Guadalupe
- Our Lady of Lourdes
- Our Lady of Meritxell
- Our Lady Peace (Canadian alternative rock band) Our Lady Peace
- Our Revolution: U.S. progressive political organization born from Sanders 2016 campaign Our Revolution
- Our Version of Events — Emeli Sandé’s debut studio album Our Version of Events
- Ouran High School Host Club
- Ouranosaurus: the sail-backed iguanodontid of Early Cretaceous Africa Ouranosaurus
- Ouray County, Colorado
- Ourense — city in Galicia, Spain Ourense
- Ouro Preto — historic mining town in Minas Gerais, Brazil Ouro Preto
- Ouroboros: Symbol of Self-Consumption and Renewal Ouroboros
- Ourton — commune in Pas-de-Calais, northern France Ourton
- Ousby — village and civil parish in Eden, Cumbria Ousby
- Ousmane Tanor Dieng
- Ousse — commune in Pyrénées-Atlantiques, southwestern France Ousse
- Out (baseball): Definition, common plays, and significance Out (baseball)
- Out of Africa: modern human origins and global dispersal Out of Africa
- Out of Africa (1985 film) Out of Africa (movie)
- Out-of-Body Experience (OBE): Overview, Causes, and Significance Out of body experience
- Out of the Game (Rufus Wainwright album) Out of the Game
- Out of the Woods (song)
- Out to Sea (1997 film) Out to Sea
- Out-of-order execution in modern processors Out-of-order execution
- Outagamie County, Wisconsin
- Outasight: American singer–rapper blending hip hop, soul and classic rock Outasight
- Outback (Australia): remote interior landscapes, people and uses Outback
- Outboard motor: design, types, history and uses Outboard motor
- Outbreak (epidemiology): causes, characteristics, and public health response Outbreak
- Outcast of Redwall
- Outcrossing (genetics) Outcrossing
- Outeniqua Mountains — South African range on the Garden Route Outeniqua Mountains
- Outer Banks (North Carolina): Barrier Islands, History, and Ecology Outer Banks
- Outer Hebrides (Western Isles): islands, culture, history, and wildlife Outer Hebrides
- Outer Planets of the Solar System Outer planet
- Outer space: overview, structure, history, and importance Outer space
- Outerbridge Crossing
- Outfield assist (baseball) Outfield assist
- Outfielder (baseball) Outfielder
- Outflow (meteorology): thunderstorm downdrafts, gust fronts and boundaries Outflow (meteorology)
- Outhouse: Outdoor Simple Toilet Structures and Their Variants Outhouse
- Outi Ojala — Finnish Left Alliance politician and Nordic Council president Outi Ojala
- Outkast: American hip hop duo that reshaped Southern rap Outkast
- Outland (1981 film) Outland (movie)
- Outlaw (legal and cultural concept) Outlaw
- Outlaw Biker Films: History, Themes and Cultural Influence Outlaw biker movie
- Outlaw motorcycle club
- Outlaw's Daughter (1954 film) Outlaw's Daughter
- Outlaws (American Southern rock band) Outlaws (band)
- Outlook Express — overview, history, features, and legacy Outlook Express
- Outlook, Saskatchewan: prairie town and home of the Skytrail Outlook, Saskatchewan
- Outlook.com — Microsoft's consumer webmail and personal information service Outlook.com
- Outnumbered (British television sitcom) Outnumbered
- Outokumpu — town in North Karelia, Finland Outokumpu
- Output (result produced by a system, device, or process) Output
- Output device (computer peripheral) Output device
- Outrage (2010 film) — Takeshi Kitano's yakuza drama Outrage (movie)
- Outram Park MRT Station
- Outreau: Commune in Pas-de-Calais, northern France Outreau
- Outriaz — commune in Ain, Auvergne‑Rhône‑Alpes, eastern France Outriaz
- Outrigger skis: adaptive ski aids for balance, turning and braking Outrigger skis
- Outsider art
- Outsider in the White House
- Outsourcing: practice, models, history and implications Outsourcing
- Outstation (Aboriginal homeland) — small family settlements in Australia Outstation
- Outstation (Aboriginal community)
- Outwash plain (glacial outwash) Outwash plain
- Ouve-Wirquin — commune in Pas-de-Calais, northern France Ouve-Wirquin
- Ouveillan — commune in Aude, Occitanie, southern France Ouveillan
- Ouville-la-Bien-Tournée — former Calvados commune now part of Saint-Pierre-en-Auge Ouville-la-Bien-Tournée
- Ouzinkie, Alaska
- Oval (shape): definition, characteristics, history and uses Oval
- Oval Office
- Oval tube station
- Ovaltine
- Ovanåker Municipality
- Ovarian cancer: overview, types, risk factors and management Ovarian cancer
- Ovary — structure, function, and variation in animals Ovary
- Ove Verner Hansen: Danish opera singer and character actor Ove Verner Hansen
- Oven: Types, Function, History and Uses Oven
- Over (cricket)
- Over and Over — Nelly featuring Tim McGraw Over and Over
- Over My Head (Cable Car) — debut single by The Fray Over My Head (Cable Car)
- Over the Hedge (2006 film) Over the Hedge (movie)
- Over the Limit (2010) — inaugural WWE pay-per-view in Detroit Over the Limit (2010)
- Over the Limit (2011) — WWE pay-per-view event Over the Limit (2011)
- Over the Limit (2012) — WWE pay-per-view in Raleigh, North Carolina Over the Limit (2012)
- Over the Rainbow: origin, context, and cultural legacy Over the Rainbow
- Over the River and Through the Wood: Lydia Maria Child’s Thanksgiving Poem Over the River and Through the Wood
- Over-harvesting: causes, impacts and approaches to sustainable use Over-harvesting
- Over-the-counter drug (OTC): definition, regulation, and safe use Over-the-counter drug
- Overbetuwe (municipality in Gelderland, Netherlands) Overbetuwe
- Overboard (2018 film) Overboard (2018 movie)
- Overbrook, Kansas — small city in Osage County Overbrook, Kansas
- Overburden: definition, composition, removal and environmental issues Overburden
- Overcharge (economics and antitrust law) Overcharge
- Overclocking: Increasing the speed of CPUs, GPUs and other components Overclocking
- Overcoat: long outer garments for warmth and style Overcoat
- Overdinkel: Dutch village on the Dinkel river near the German border Overdinkel
- Overdose (drug poisoning): causes, effects, and emergency response Overdose
- Overdose (EP) — Exo Overdose (EP)
- Overdubbing — adding recorded sounds to an existing performance Overdubbing
- Overexposed (Maroon 5 album) Overexposed (album)
- Overfishing: causes, consequences, and responses Overfishing
- Overhand knot
- Overhead lines (electrical) — systems for supplying power to traction vehicles Overhead lines
- Overhead projector: design, history, and educational uses Overhead projector