CO

CO or variants may refer to:

People

• Nguyễn Hữu Có (1925–2012), a Vietnamese general

Places

• CO postcode area, or Colchester postcode area, England
• Colombia, in various country codes
• Colorado (United States postal abbreviation)

Ranks and titles

• Commanding officer, the officer in command of a military unit
• Contracting Officer (CO or KO), in the U.S. government
• C.O., post-nominal initials of members of the congregation of the Oratory of Saint Philip Neri

Science, technology and mathematics

Biology and medicine

• Cardiac output (CO), the volume of blood being pumped by the heart per time unit

Chemistry

• Cobalt, a chemical element, symbol Co
• Carbon monoxide (CO), a colorless, odorless, and tasteless gas
• Carbonyl group, composed of a carbon atom double-bonded to an oxygen atom: C=O

Electronics and computing

• .co, the Internet top-level domain for Colombia
• .co (second-level domain), Internet second-level domain meaning "commercial"
• Commitment ordering (CO), a concurrency control technique for databases

Mathematics

• Cofunction in trigonometry

Transport

• Chemins de fer Orientaux (CO), a former Ottoman railway company
• Chesapeake and Ohio Railway (C&O or CO), a former American railroad
• Continental Airlines (IATA airline designator CO), an American airline before 2012
• Cobalt Air (IATA airline designator CO), a Cypriot airline from 2016

Other uses

• Certificate of occupancy (CO), a legal document
• Certificate of origin (often abbreviated to C/O or CoO), in international trade
• Company (abbreviated co.)
• Corsican language, ISO 639-1 language code co
• Counties of Ireland, abbreviated Co.
• co-, an English prefix meaning coming together
• Telephone exchange, or Central office (CO)
• Castres Olympique, a French rugby club

See also

• C0 (disambiguation), the letter-number combination
• Care of (disambiguation)
• Co-Co locomotives