Main definitions of co in US English:

: Co1CO2

Co1

  • The chemical element cobalt.

Main definitions of co in US English:

: Co1CO2

CO2

  • 1Colorado (in official postal use).

  • 2Commanding Officer.

    leader, head, headman, boss, chief, director, manager, overseer, controller, master
    View synonyms
  • 3Conscientious objector.

Pronunciation

CO

/ˌsiˈoʊ//ˌsēˈō/