Definitions of co

1. With; together See COM-. Co is often joined to purely English words; as, comate, copartner, corespondent ( distinguished from correspondent).

2. a heavy odorless colorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis

3. an odorless very poisonous gas that is a product of incomplete combustion of carbon

4. a state in west central United States in the Rocky Mountains

5. one who refuses to serve in the armed forces on grounds of conscience

6. A prefix of Latin origin; ao abbreviation for company. See Con.

7. A form of the prefix con, and means, with; together; together with; co is used before a vowel and h, as coalesce, cohabit, and is often separated from the word by a hyphen, as co- operate, co- partner; in math., co is an abbreviation of complement, as co- latitude, co- sine, co- tangent. Note.- The prefix con assumes the various forms of co, cog, col, com, cor, according to the first letter of the second element of the compound; but, 1, con becomes com before b and p, as combustion, compel; 2, con is retained before j and v, except in comfort, as conflict, convene; 3, con is retained before t, d, q, g, and s, as content, condole, conquest, congeal, consent.