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• Co
  Co

  cobalt.
• CO
  CO

  abbreviation

  Colorado (approved especially for use with zip code).
• Co.
  Co.

  abbreviation

  Company.
• c/o
  c/o

  care of.
• C/o
  C/o

  care of.
• C/O
  C/O

  cash order.
• co-
  co-

  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 ).
• c.o.
  c.o.

  abbreviation

  care of.
• C.O.
  C.O.

  abbreviation

  cash order.
• co
  co

  abbreviation

  a commercial company (used with a country domain name)

Co

¹ American  

Symbol, Chemistry.

1. cobalt.

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CO ² American  

abbreviation

1. Colorado (approved especially for use with zip code).

2. commanding officer.

3. conscientious objector.

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Co. ³ American  

Or co.

abbreviation

1. Company.

2. County.

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c/o ⁴ American  

1. care of.

2. Bookkeeping. carried over.

3. cash order.

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C/o ⁵ American  

1. care of.

2. Bookkeeping. carried over.

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C/O ⁶ American  

1. cash order.

2. certificate of origin.

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co- ⁷ American  

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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c.o. ⁸ American  

abbreviation

1. care of.

2. carried over.

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C.O. ⁹ American  

abbreviation

1. cash order.

2. Commanding Officer.

3. conscientious objector.

4. correction officer.

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CO ¹ British  

abbreviation

1. Commanding Officer

2. Commonwealth Office

3. conscientious objector

4. Colorado

5. Colombia (international car registration)

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co- ² British  

prefix

1. together; joint or jointly; mutual or mutually

   coproduction

2. indicating partnership or equality

   cofounder

   copilot

3. to the same or a similar degree

   coextend

4. (in mathematics and astronomy) of the complement of an angle

   cosecant

   codeclination

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Co ³ British  

abbreviation

1. (esp in names of business organizations) Company

2. informal and the rest of them

   Harold and co

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c/o ⁴ British  

abbreviation

1. care of

2. accounting carried over

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co ⁵ British  

abbreviation

1. a commercial company (used with a country domain name)

2. Colombia

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Co ⁶ British  

symbol

1. cobalt

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Co ⁷ British  

abbreviation

1. County

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Etymology

Origin of co-

from Latin, reduced form of _com-

Example Sentences

It should also help Intel more closely compete with contract chip-making giant Taiwan Semiconductor Manufacturing Co.

From The Wall Street Journal • Jun. 23, 2026

He eventually left Columbia to take a position at an economic consulting firm that eventually became known as Townsend-Greenspan Co.

From MarketWatch • Jun. 22, 2026

Co, the police spokesman, also revealed the other weapon used in the shooting, a .38 calibre pistol, was registered to a security agency in Cebu City.

From Barron's • Jun. 22, 2026

While we were in rehearsals, me and the band, a couple nights before our first show, went to see Dead & Co.

From Los Angeles Times • Jun. 18, 2026

One of the letters was directed to Samuel F. Billington, No. 7, The Crescent, Whitby, another to Herr Leutner, Varna; the third was to Coutts & Co.,

From "Dracula" by Bram Stoker