commander

UK: /kəˈmɑːndə^r/ US: /kəˈmændɚ/ ,(kə man′dər, -män′-)

WordReference Random House Learner's Dictionary of American English © 2026

com•mand•er /kəˈmændɚ/   n. [countable]

1. a person in authority;
   chief officer;
   leader.
2. Military the officer in command of a military unit.
3. Military an officer in the U.S. Navy or Coast Guard ranking below a captain and above a lieutenant commander.

WordReference Random House Unabridged Dictionary of American English © 2026

com•mand•er  (kə man′dər, -män′-), n. 

1. a person who commands.
2. a person who exercises authority;
   chief officer;
   leader.
3. Military the commissioned officer in command of a military unit.
4. Military [U.S. Navy.] an officer ranking below a captain and above a lieutenant commander.
5. a police officer in charge of a precinct or other unit.
6. World History the chief officer of a commandery in the medieval orders of Knights Hospitalers, Knights Templars, and others.
7. World History a member of one of the higher classes or ranks in certain modern fraternal orders, as in the Knights Templars.

• Latin -ātōr- -ator
• Old French comandere, equivalent. to comand(er) to command + -ere
• Middle English 1250–1300

com•mand′er•ship′, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

commander / kəˈmɑːndə/ noun

1. an officer in command of a military formation or operation
2. a naval commissioned rank junior to captain but senior to lieutenant commander
3. the second in command of larger British warships
4. someone who holds authority
5. a high-ranking member of some knightly or fraternal orders
6. an officer responsible for a district of the Metropolitan Police in London

comˈmanderˌship noun