warrant officer

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

• noun A military officer, usually a skilled technician or a helicopter pilot, intermediate in rank between a noncommissioned officer and a commissioned officer, having authority by virtue of a warrant.

from The Century Dictionary.

• noun An officer who acts under a warrant from a department of the government, and not from the sovereign or head of the state as in the case of commissioned officers.

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

• noun A member of a military organization having a rank between that of a commissioned and non-commissioned officer

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

• noun holds rank by virtue of a warrant