noncommissioned officer

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An enlisted member of the armed forces, such as a corporal, sergeant, or petty officer, appointed to a rank conferring leadership over other enlisted personnel.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A person of authority in the military who has not received a commission (a direct conveyance of authority from the sovereign government); as such they can have charge or control but not command in the most technical use of the word.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a military officer appointed from enlisted personnel