observer: Meaning and Definition of

ob•serv•er

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.
1. a member of an aircrew, other than the pilot, holding an aeronautical rating.
2. a person who maintains observation in an aircraft during flight.
4. Also calleda person who serves in an aircraft as a reconnoiterer and directs artillery fire.