1) Commandant 2) Commander 3) Commander in chief 4) Commanding officer 5) Military rank 1) Commandant 
An Italian term meaning 
• (a.) The chief commander of an army; especially, the commander in chief of an army consisting of two or more grand divisions under separate commanders; -- a title used in most foreign countries.
Gen`er·al·is'si·mo noun [ Italian , superl. of generale general. See General , adjective ] The chief commander of an army; especially, the commander in chief of an army consisting of two or more grand divisions under separate commanders; -- a title used in most fo...