com·mand·er 
(kə-măndər)
(kə-măndər)n.
1. A person who commands, especially a commanding officer.
2.
a. A commissioned rank in the US Navy or Coast Guard that is above lieutenant commander and below captain.
b. One who holds this rank.
c. The chief commissioned officer of a military unit regardless of his or her rank.
3. An officer in some knightly or fraternal orders.