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Co

See more synonyms for Co on Thesaurus.com
Symbol, Chemistry.
  1. cobalt.
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CO

  1. Colorado (approved especially for use with zip code).
  2. Commanding Officer.
  3. conscientious objector.
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co-

  1. variant of com- before a vowel, h, and gn: coadjutor; cohabit; cognate. The prefix co- now productively forms new words from bases beginning with any sound (co-conspirator; co-manage; coseismic), sometimes with the derived sense “auxiliary, subsidiary” (coenzyme; copilot), and, in mathematics and astronomy, with the sense “complement” (codeclination).
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Co.

or co.

c.o.

  1. care of.
  2. carried over.
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c/o

  1. care of.
  2. Bookkeeping. carried over.
  3. cash order.
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C/o

  1. care of.
  2. Bookkeeping. carried over.
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C.O.

  1. cash order.
  2. Commanding Officer.
  3. conscientious objector.
  4. correction officer.
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C/O

  1. cash order.
  2. certificate of origin.
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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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British Dictionary definitions for co

co

the internet domain name for
  1. a commercial company (used with a country domain name)
  2. Colombia
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Co1

the chemical symbol for
  1. cobalt
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Co2

abbreviation for
  1. County
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Co3

co

abbreviation for
  1. (esp in names of business organizations) Company
  2. and co (kəʊ) informal and the rest of themHarold and co
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CO

abbreviation for
  1. Commanding Officer
  2. Commonwealth Office
  3. conscientious objector
  4. Colorado
  5. Colombia (international car registration)
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co-

prefix
  1. together; joint or jointly; mutual or mutuallycoproduction
  2. indicating partnership or equalitycofounder; copilot
  3. to the same or a similar degreecoextend
  4. (in mathematics and astronomy) of the complement of an anglecosecant; codeclination
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Word Origin

from Latin, reduced form of com-

c/o

abbreviation for
  1. care of
  2. accounting carried over
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for co

co-

in Latin, the form of com- in compounds with stems beginning in vowels and h- and gn- (see com-). Taken in English from 17c. as a living prefix meaning "together, mutually, in common," and used promiscuously with native words and Latin-derived words not beginning with vowels, sometimes even with words already having it (e.g. co-conspiritor).

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c/o

addressing abbreviation for care of; "common" by 1889.

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co.

abbreviation of company, attested by 1670s.

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Online Etymology Dictionary, © 2010 Douglas Harper

co in Medicine

Co

  1. The symbol for the elementcobalt

co-


co in Science

Co

cobalt

[kōbôlt′]
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.