Definition of: officer

(ô′fə·sər, of′ə-) noun
1. One elected or appointed to office, as in a company, a society, or an ecclesiastical body, or one filling some other semipublic position, as by appointment.
2. One appointed to a certain military or naval rank and authority, specifically by commission.
3. In the merchant marine, etc., the captain or any of the mates.
4. A member of the constabulary or police force.
5. In corporate bodies and other organizations, one who holds a position entailing certain duties, as secretary or treasurer, as distinguished from an employee.
—commissioned officer An officer who receives a commission, ranking, in the U.S. Army, from second lieutenant to general, and in the U.S. Navy from ensign to admiral.
—line officer An officer of a combat branch of the service; officer of the line.
—non-commissioned officer An officer appointed from the military ranks by an authorized commanding officer. The non-commissioned grades rank from corporal through master sergeant.
—warrant officer In the U.S. Army, Navy, Air Force, Marine Corps, and Coast Guard, an officer without a commission, but having authority by virtue of a certificate or warrant. His rank is superior to that of a non-commissioned officer. See table under GRADE.
—v.t.
1. To furnish with officers.
2. To command; direct; manage. [<AF officer, OF officier <Med. L officarius <L officium OFFICE]