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Columbia Encyclopedia

Columbia Electronic Encyclopedia, published by Columbia University Press
The Columbia Electronic Encyclopedia contains entries on people, places, events, historical facts and terms, with bibliographies for further reading.
On this page: Ops to Ordovician period.
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Title Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0-9
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Ops (in Roman mythology)
optical activity (in optics)
optical disk (in communication, music, film, computers)
optical sensing (in optics)
optician (in medicine)
optics (branch of optics, physics)
optometry (branch of medicine)
opus (in music)
Opus Dei (Roman Catholic prelature)
oracle (ancient religion, ancient Greece)
oracle bones (linguistics, China)
Oradea (city, Romania)
Öraefajökull (mountain, Iceland)
Oraibi (structure, Arizona)
Oral (city, Kazakhstan)
oral history (in history)
Oran (city, Algeria)
Orange (Princely family of Europe ruling)
orange (in botany)
Orange (city, Connecticut)
Orange (city, New Jersey)
Orange (city, Texas)
Orange (city, California)
Orange Free State (province, South Africa)
Orange River (river, Africa)
Orangeburg (city, South Carolina)
Orangemen (organization, Ireland)
orangutan (primate)
Oranienburg (city, Germany)
Oranjestad (capital, Aruba)
oratorio (in music)
oratory (order)
orbit (in astronomy)
Orbiting Astronomical Observatory (in astronomy, space)
Orbiting Geophysical Observatory (in geology, physics, space)
Orbiting Solar Observatory (in astronomy, space)
orchard (tree)
orchid (flower, herb)
Orchomenus (ancient city, ancient Greece)
ordeal (in law)
orders in council (government, England)
orders of architecture (in architecture)
orders, holy (in Christianity)
Ordinance of 1787 (law, United States)
Ordos (region, China)