Commander is a military rank used in many navies—but not generally used in armies or air forces—below Captain and above Lieutenant-Commander. Formerly the rank was Master and Commander, and Commanders traditionally are known as Captain by courtesy.
A Commander in the U.S. Navy is leading a Frigate Destroyer, or Submarine or shore instalation, or is second of a Captain.
Sometimes the term kommandant is used.
In Fiction
See also