commander

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A person who commands, especially a commanding officer.
2. n. A commissioned rank in the U.S. Navy or Coast Guard that is above lieutenant commander and below captain.
3. n. One who holds this rank.
4. n. The chief commissioned officer of a military unit regardless of his or her rank.
5. n. An officer in some knightly or fraternal orders.

Century Dictionary and Cyclopedia

1. n. One who has the authority or power to command or order; especially, a military leader; the chief officer of an army or of any division of it.
2. n. Hence One who has control, in any sense.
3. n. Specifically In the British and United States navies, an officer next in rank below a captain and above a lieutenant or a lieutenant-commander. He may command a vessel of the third or fourth class, or may be employed as chief of staff to a commodore on duty under a bureau, as aid to a flag-officer, etc. In the navy of the United Stales the commander ranks with a lieutenant-colonel in the army. Often, as a title, abbreviated Com.
4. n. The chief officer of a commandery in the medieval orders of Knights Hospitallers, Templars, etc. See commandery, 2 .
5. n. A similar officer in certain secret orders, as in the American order of Knights Templars.
6. n. A member of a higher class in a modern honorary order. Where there are five classes, the commanders are the third in dignity; where there are three, they are generally the second: as, a commander of the Bath.
7. n. A heavy beetle or wooden mallet used in paving, or by sailmakers and riggers.
8. n. In surgery, a box or cradle for incasing an injured limb.
9. n. In hat-making, a string which is pressed down over a conical hat while it is on the block, to bring it to the required cylindrical form.
10. n. In medieval fortification, same as cavalier, 5.
11. n. A member of the highest class, or one of the highest classes, of some modern honorary orders. See order. Synonyms Leader, Head, etc. See chief.

Wiktionary

1. n. One who exercises control and direction of a military or naval organization.
2. n. A naval officer whose rank is above that of a lieutenant commander and below that of captain.
3. n. One who exercises control and direction over a group of persons.
4. n. A designation or rank in certain non-military organizations such as NASA and various police forces.
5. n. obsolete The chief officer of a commandry.
6. n. A heavy beetle or wooden mallet, used in paving, in sail lofts, etc.

GNU Webster's 1913

1. n. A chief; one who has supreme authority; a leader; the chief officer of an army, or of any division of it.
2. n. (Navy) An officer who ranks next below a captain, -- ranking with a lieutenant colonel in the army.
3. n. The chief officer of a commandery.
4. n. A heavy beetle or wooden mallet, used in paving, in sail lofts, etc.

WordNet 3.0

1. n. an officer in command of a military unit
2. n. an officer in the airforce
3. n. a commissioned naval officer who ranks above a lieutenant commander and below a captain
4. n. someone in an official position of authority who can command or control others