CO

CO, Co, co, .co, c/o ℅ may refer to:

Computing and technology

• .co, the Internet top-level domain for Colombia
• .co (second-level domain), Internet second-level domain used to denote commercial organizations in many countries
• Changeover switch, a type of electrical switch with both types of opened/closed contacts
• Commitment ordering or Commit ordering, a concurrency control (serializability) technique for databases and transactional systems

Science and medicine

• Co, the chemical symbol for the element cobalt
• Carbon monoxide, the molecular formula of the toxic gas (also called Carbonous oxide)
• Cardiac output, the volume of blood being pumped by the heart per time unit
• Coccygeal nerve of the spinal cord

Geographic codes

• Co., an abbreviation for county
• CO postcode area for Colchester, England
• Colombia, in various country codes
• Colorado (United States postal abbreviation)
• Como, Lombardia, Italy

Transport

• Chemins de fer Orientaux, an Ottoman railway company
• Chesapeake and Ohio Railway
• Continental Airlines, IATA airline designator

People and official titles

• Nguyễn Hữu Có (1925–2012), Vietnamese general
• C.O., post-nominal initials to identify members of the congregation of the Oratory of Saint Philip Neri
• Certified Orthotist
• Chief Officer
• Commanding officer, military
• Commissioned officer, military
• Communications Officer in Central Communications Command
• Conscientious objector, military
• Conservation officer
• Contracting Officer
• Corrections Officer (or Correctional Officer)

Other uses

• co, an English prefix meaning coming together (co-operate, co-curricular activities, co-brother etc.)
• co, a gender-neutral pronoun
• co (function prefix) (complementary), a prefix for complementary functions in mathematics
• ℅, care of, used to address a letter when the letter must pass through an intermediary (also written c/o)
• Central office, in telecommunications and telephony
• Certificate of occupancy, a legal document
• Certificate of origin, used in international trade
• Company (co.), a general business abbreviation
• Corsican language, ISO 639 alpha-1

See also

• C0 (disambiguation), the letter-number combination