Pronunciation: (ub-zûr'vur),[key] —n. 1. someone or something that observes.
2. a delegate to an assembly or gathering, who is sent to observe and report but not to take part officially in its activities.
3. U.S. Air Force. a. a member of an aircrew, other than the pilot, holding an aeronautical rating.
b. a person who maintains observation in an aircraft during flight.
4. Also called air observer, aircraft observer.U.S. Army.a person who serves in an aircraft as a reconnoiterer and directs artillery fire.