co Meaning, Definition & Usage

1. noun an odorless very poisonous gas that is a product of incomplete combustion of carbon
   carbon monoxide gas; carbon monoxide.
   
2. noun a hard ferromagnetic silver-white bivalent or trivalent metallic element; a trace element in plant and animal nutrition
   atomic number 27; cobalt.
   
3. noun one who refuses to serve in the armed forces on grounds of conscience
   conscientious objector.
   
4. noun a state in west central United States in the Rocky Mountains
   Centennial State; Colorado.
   

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