CO or variants may refer to:

Chemistry

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

Computing and telecommunications

* .co (second-level domain), the Internet second-level domain meaning "commercial" *

.co .co is the Internet country code top-level domain (ccTLD) assigned to Colombia. It is administered by .CO Internet S.A.S.,

, the Internet country code top-level domain (ccTLD) for Colombia * Commitment ordering (CO), a concurrency control technique for databases *

Telephone exchange A telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital syst ...

, or central office (CO)

Mathematics

* Cofunction, or Co, in trigonometry * Cuboctahedron, a uniform polyhedron

People

Nguyễn Hữu Có Nguyễn Hữu Có ( ; 23 February 1925 – 3 July 2012) was a South Vietnamese soldier and politician who served in the Army of the Republic of Vietnam, rising to the rank of lieutenant general. He was prominent in several coups and juntas ...

(1925–2012), Vietnamese general * Conrado Co (born 1940), Filipino badminton player *

Alfredo Co Alfredo Pimentel Co (; born on November 30, 1949) is a Filipino Sinologist and philosopher.
.' ...

(born 1949), Filipino Sinologist * Atoy Co (born 1951), Filipino actor and basketball coach *

Leonard Co Leonardo Legaspi Co (December 29, 1953 in Manila – November 15, 2010 in Kananga, Leyte) was a Filipino botanist and plant taxonomist who was considered the "foremost authority in ethnobotany in the Philippines" during his lifetime. Education a ...

(1953–2010), Filipino botanist * Nando Có (born 1973), Bissau-Guinean footballer *

Kenedy Có Kenedy Silva Có (born 30 November 1998) is a Guinea-Bissauan professional footballer who plays as a forward for Campeonato de Portugal club Camacha. Club career On 20 August 2017, Có made his professional debut with Sporting B in a 2017–18 ...

(born 1998), Bissau-Guinean footballer *

Samuel S. Co Samuel "Sammy" Sy Co is a Chinese Filipino businessman and politician, who currently serves as the incumbent Mayor of Pagadian City. He had also served as city councilor of Pagadian for three terms. Co first won the Mayoralty position of Pagadian ...

, Filipino politician

Places

* CO postcode area, or Colchester postcode area, England *

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

, ISO 3166-1 country code CO * Colorado, United States postal abbreviation CO *

Counties of Ireland The counties of Ireland (Irish language, Irish: ) are historic administrative divisions of the island into thirty-two units. They began as Norman structures, and as the powers exercised by the Cambro-Norman barons and the Old English (Ireland) ...

, abbreviated Co.

Ranks and titles

* C.O., post-nominal initials of members of the congregation of the

Oratory of Saint Philip Neri The Confederation of Oratories of Saint Philip Neri ( la, Confoederatio Oratorii Sancti Philippi Nerii) abbreviated CO and commonly known as the Oratorians is a Catholic society of apostolic life of Pontifical Right for men (priests and lay- ...

* C/O, cadet officer ranks of the Junior Reserve Officers' Training Corps * Commanding officer (CO), the officer in command of a military unit * Contracting Officer (CO or KO), in the U.S. government * Correctional officer (CO), an officer whose duty it is to safeguard and promote the welfare of inmates * Circle officer (CO), in the Indian government * Conscientious objector

Transportation

* Chemins de fer Orientaux (CO), a former Ottoman railway company * Chesapeake and Ohio Railway (C&O or CO), a former American railroad * Cobalt Air (IATA airline designator CO, 2016-2018), a Cypriot airline * Continental Airlines (IATA airline designator CO, 1937-2012), an American airline

Other uses

* co-, an English prefixes, English prefix meaning coming together * Cardiac output (CO), the volume of blood being pumped by the heart per time unit * Castres Olympique, a French rugby club * 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 * , a Unicode character in the Letterlike Symbols block * c/o, former name of Gerhardsen Gerner, an art gallery in Berlin