Search by letter: O
Search by letter
Search by letter: O
- Overijse: Flemish Brabant municipality known for vineyards and woodland Overijse
- Overijssel: Dutch province east of the IJssel Overijssel
- Överkalix: a northern Swedish locality and municipal centre Överkalix
- Överkalix Municipality (Norrbotten County, Sweden) Överkalix Municipality
- Overkill (American thrash metal band) Overkill
- Overland Campaign (May–June 1864): Grant vs. Lee in the Eastern Theater Overland Campaign
- Overland Relief Expedition (Point Barrow rescue, 1897–1898) Overland Expedition
- Overland Park, Kansas
- Overlord
- Overlord (novel series)
- Overpass: purpose, types, design and role in transportation Overpass
- Overpelt (former municipality in Limburg, Belgium) Overpelt
- Overpopulation: Causes, Consequences, and Responses Overpopulation
- Overseas departments of France
- Overseas France (France d'outre-mer) Overseas France
- Overton County, Tennessee
- Overton's 400 (Monster Energy NASCAR Cup Series race) Overton's 400
- Övertorneå: town in northern Sweden on the Torne River Övertorneå
- Övertorneå Municipality
- Overture: musical opening, development, forms, and notable examples Overture
- Overweight: definition, measurement, causes, health effects and social aspects Overweight
- Oveta Culp Hobby: Army leader, federal official, and media executive Oveta Culp Hobby
- Ovid (village), New York
- Ovidio Messa — Bolivian footballer and national team player (1952–2017) Ovidio Messa
- Oviedo — capital of the Principality of Asturias, northern Spain Oviedo
- Oviedo, Florida
- Ovillers-la-Boisselle: commune and First World War battlefield in the Somme Ovillers-la-Boisselle
- Ovington (Braintree District, Essex) Ovington
- Oviparous animals: egg-laying reproduction and its diversity Oviparous animals
- Ovipositor: insect egg-laying organ and its forms Ovipositor
- Oviraptor — toothless, crested theropod of the Late Cretaceous Oviraptor
- Oviraptorosaurs: the beaked, feathered maniraptorans of the Cretaceous Oviraptorosaur
- Ovis — genus of sheep (wild and domestic) Ovis
- Oviya (2018 Tamil television series) Oviya (TV series)
- Ovo je Balkan: Milan Stanković's Eurovision 2010 Song for Serbia Ovo je Balkan
- Ovodda: town and comune in central Sardinia Ovodda
- Ovule (plant structure that gives rise to seeds) Ovule
- Ovum (egg) — the female reproductive cell Ovum
- Ōwa (Japanese era, 961–964) Ōwa
- Owain Glyndŵr — Welsh leader and national symbol Owain Glyndŵr
- Owari Province (尾張国) Owari Province
- Owasa, Iowa
- Owasso, Oklahoma: Overview, History, and Community Owasso, Oklahoma
- Owatonna, Minnesota
- Owen Arthur
- Owen Bieber: UAW Leader During a Transformative Era in the Auto Industry Owen Bieber
- Owen Chadwick (1916–2015) — British historian of Christianity Owen Chadwick
- Owen County, Indiana: overview, geography, history, and communities Owen County, Indiana
- Owen County, Kentucky
- Owen Garriott — American electrical engineer and astronaut Owen Garriott
- Owen Hargreaves: career, playing style, injuries and post‑playing work Owen Hargreaves
- Owen Hart: Canadian professional wrestler, performer and legacy Owen Hart
- Owen Jones (writer)
- Owen Morris (record producer) Owen Morris
- Owen Paterson (British politician) Owen Paterson
- Owen Roizman — American cinematographer Owen Roizman
- Owen Smith (British Labour politician) Owen Smith
- Owen Sound, Ontario Owen Sound
- Owen Spencer-Thomas: British broadcaster, Anglican clergyman and fundraiser Owen Spencer-Thomas
- Owen Wilson
- Owen Woodhouse: New Zealand jurist and architect of no‑fault accident compensation Owen Woodhouse
- Owens Lake
- Owensboro, Kentucky — river city, culture, and regional center Owensboro, Kentucky
- Owenton, Kentucky — Overview of the County Seat of Owen County Owenton, Kentucky
- Owingsville, Kentucky
- Owl (Strigiformes): biology, behavior and global distribution Owl
- Owl City
- Owl Nebula (Messier 97) Owl nebula
- Ownership: Concepts, Rights, Forms, and Historical Context Ownership
- Owsley County, Kentucky
- Owsley "Bear" Stanley: LSD chemist and Grateful Dead sound innovator Owsley Stanley
- Owyhee County, Idaho
- Ox Baker (Douglas A. Baker) — American professional wrestler and actor Ox Baker
- Ox Mountain: Mencius’s parable on environment, nature, and moral nurture Ox Mountain
- Öxabäck — small locality in Mark Municipality, Sweden Öxabäck
- Öxabäcks IF — Swedish sports club noted for pioneering women's football Öxabäcks IF
- Oxalaia — a spinosaurid theropod from the Cretaceous of Brazil Oxalaia
- Oxalidaceae — the wood-sorrel family of flowering plants Oxalidaceae
- Oxalidales — an order of flowering plants Oxalidales
- Oxberg — small locality in Mora Municipality, Dalarna, Sweden Oxberg
- Oxbow Lake: formation, characteristics, and ecological importance Oxbow lake
- Oxbridge: the historic partnership and rivalry of Oxford and Cambridge Oxbridge
- Oxegen — Irish multi‑day music festival at Punchestown (2004–2013) Oxegen
- Oxelösund
- Oxelösund Municipality
- Oxfam: International confederation for poverty relief, development and advocacy Oxfam
- Oxford: city, university, architecture, and history Oxford
- Oxford Circus
- Oxford Circus tube station
- Oxford County, Maine
- Oxford East (UK Parliament constituency)
- Oxford English Dictionary
- Oxford Junction, Iowa
- Oxford Movement (Tractarianism): 19th‑century revival in the Church of England Oxford Movement
- Oxford Street — major shopping thoroughfare in London's West End Oxford Street
- Oxford United F.C.
- Oxford University Press: history, structure, and global publishing Oxford University Press
- Oxford, Alabama
- Oxford, Connecticut — residential town in New Haven County Oxford, Connecticut
- Oxford, Idaho
- Oxford, Indiana
- Oxford, Iowa: overview of a small Midwestern city Oxford, Iowa
- Oxford, Mississippi: College town, history, and cultural center Oxford, Mississippi
- Oxford, Nova Scotia
- Oxford, Ohio: Miami University and a classic American college town Oxford, Ohio
- Oxfordshire
- Oxfordshire Ironstone Railway (Wroxton quarry line) Oxfordshire Ironstone Railway
- Oxidation state (oxidation number) Oxidation state
- Oxide (chemical compounds of oxygen and other elements) Oxide
- Oxidizing agent (oxidant): definition, properties, examples and uses Oxidizing agent
- Oxnard, California — Coastal city and agricultural center Oxnard, California
- OXO (video game)
- Oxon Hill, Maryland
- Oxpecker (Buphagidae): African birds that cling to large mammals Oxpecker
- Oxycodone: overview, properties, uses, history and safety Oxycodone
- Oxygen (element O) Oxygen
- Oxygen (TV channel)
- Oxygen difluoride (OF2) Oxygen difluoride
- Oxygen saturation: dissolved oxygen in water and oxygenation in blood Oxygen saturation
- Oxygen therapy: definition, delivery methods, uses, risks and history Oxygen therapy
- Oxygen-18 (18O): a stable isotope of oxygen Oxygen-18
- Oxymoron: Contradictory Expressions in Language and Rhetoric Oxymoron
- Oxytocin: the peptide hormone and neuropeptide Oxytocin
- Oy-Mittelberg — municipality in Oberallgäu, Bavaria Oy-Mittelberg
- Oya Aydoğan: Turkish actress, model and television presenter Oya Aydoğan
- Oyanagi Shigeta (1870–1940) — Japanese scholar of Chinese literature and Taoism Oyanagi Shigeta
- Oye-Plage, commune in Pas-de-Calais Oye-Plage
- Oyens, Iowa
- Oyo State (Nigeria): overview, history, geography, economy and culture Oyo State
- Oyonnax — industrial town in Ain, Auvergne-Rhône-Alpes Oyonnax
- Oyster (Ostreidae): biology, harvesting, history and culinary use Oyster
- Oyster Bay, New York — town in eastern Nassau County Oyster Bay, New York
- Oyster card — London’s contactless public transport smart card Oyster card
- Oystercatcher: coastal shorebird with a specialized bill Oystercatcher
- Oz (programming language)
- Oz the Great and Powerful (2013 film) Oz the Great and Powerful
- Ozai — Fire Lord and primary antagonist of Avatar: The Last Airbender Ozai
- Ozama River (Dominican Republic) Ozama River
- Ozámiz — city in Misamis Occidental, Philippines Ozámiz
- Ozan Tufan
- Ozan (Ain) — Commune in Auvergne-Rhône-Alpes, France Ozan, Ain
- Ozark (TV series) — overview, cast, themes, production and reception Ozark (TV series)
- Ozark County, Missouri
- Ozark–St. Francis National Forest
- Ozark, Alabama
- Ozark, Arkansas
- Ozark, Missouri
- Ozarks (Ozark Plateau) — geography, geology, and cultural history Ozarks
- Ozenx-Montestrucq
- Ozieri — town and comune in Sardinia, Italy Ozieri
- Ozon (Ardèche) — commune in southern France Ozon, Ardèche
- Ozona, Texas
- Ozone (O3): properties, atmospheric role, health effects and uses Ozone
- Ozone depletion: causes, consequences, and recovery Ozone depletion
- Ozone layer: structure, chemistry, history, and global importance Ozone layer
- Ozymandias — Shelley's sonnet on impermanence and power Ozymandias
- Ozzie Newsome: NFL Hall of Famer, scouting architect, and former general manager Ozzie Newsome
- Ozzy Osbourne: life and career of the Black Sabbath frontman and solo star Ozzy Osbourne
- Ø (o with stroke) — Scandinavian letter Ø
- Øivind Holmsen
- Øyvind Bjorvatn