Comdr.

Noun

commander (plural commanders)

1. One who exercises control and direction of a military or naval organization.
   • I think if post commanders of the unchaplained posts could employ acceptable clergymen […] then the needs might be met.1883, United States. War Department, Annual Reports of the War Department, volume 1, page 128
2. A naval officer whose rank is above that of a lieutenant commander and below that of captain.
   • Shepard: I don't take orders from you anymore, remember?
     Anderson: Consider yourself reinstated... Commander.2012, BioWare, Mass Effect 3 (Science Fiction), Redwood City: Electronic Arts, →OCLC, PC, scene: Earth
3. One who exercises control and direction over a group of persons.
4. A designation or rank in certain non-military organizations such as NASA and various police forces.
5. (obsolete) The chief officer of a commandry.
6. A heavy beetle or wooden mallet, used in paving, in sail lofts, etc.

See all 10 meanings of commander