CO CO /ˈkoʊ/

noun

1. A state in west central United States in the Rocky Mountains  ( Centennial State , CO , Colo. , Colorado )
   a state in west central United States in the Rocky Mountains
   
2. One who refuses to serve in the armed forces on grounds of conscience  ( CO , conchie [Informal, UK] , conchy [Informal, UK] , conscientious objector )
   one who refuses to serve in the armed forces on grounds of conscience
     John refused to serve in the military due to his conscientious objector status.
   John refused to serve in the military due to his conscientious objector status.
   

 Co

1. A hard ferromagnetic silver-white bivalent or trivalent metallic element; a trace element in plant and animal nutrition  ( atomic number 27 , Co , cobalt )
   a hard ferromagnetic silver-white bivalent or trivalent metallic element; a trace element in plant and animal nutrition
   
   

 CO

1. An odorless very poisonous gas that is a product of incomplete combustion of carbon  ( carbon monoxide , carbon monoxide gas , CO )
   an odorless very poisonous gas that is a product of incomplete combustion of carbon