a person or thing that trains.

a staff member on an athletic team who gives first aid and therapy to injured players.

a person who trains athletes; coach.

a person who trains racehorses or other animals for contests, shows, or performances.

an airplane or a simulated aircraft used in training aircrew members, esp. pilots.

noun

adviser , breeder , coach , demonstrator , drill sergeant , guide , handler , lecturer , mentor , professor , tutor , instructor , pedagogue , teacher , drillmaster