c.o. in English

c.o.

⇄

c/o(no periods)orc.o.
1. carried over.
2. in care of.

C.O.

⇄

CO(no periods)orC.O.
an abbreviation for the following:
1. cash order.
2. Colorado (with postal Zip Code).
3. commanding officer.
4. (Informal.) conscientious objector.