teacher-n; 3 Senses

Sense Number 1: a person whose occupation is teaching

Commentary: TEACHER[+entity][+person][+occupation][+teaching]

Jane's father is a retired college teacher.
The teachers' strike lasted for six weeks.
Several of the teachers attended the senior prom as chaperones.

WordNet 3.0 Sense Numbers: 1

Sense Number 2: any personified abstraction with an instructional role

Commentary: TEACHER[+entity][+abstract][-animate][+role][+instructional]

Experience is the best teacher.
The sea was a cruel teacher for the young sailor.
Books were his only teacher during the years of isolation.

WordNet 3.0 Sense Numbers: 2

Sense Number 3: a Mormon priesthood ranking higher than a deacon

Commentary: TEACHER[+entity][+person][+priest][+Mormon][+ranked][+above_deacon]

He was a deacon in the Mormon church before becoming a teacher.

WordNet 0.0 Sense Numbers: 2