teacher

noun

1. A person who teaches, especially one employed in a school; preceptor.

   “One particularly damaging, but often ignored, effect of conflict on education is the proliferation of attacks on schools[…]as children, teachers or school buildings become the targets of attacks. Parents fear sending their children to school. Girls are particularly vulnerable to sexual violence.”

2. The index finger; the forefinger.
3. An indication; a lesson.

   “But if the last two years are a teacher, look for the bombastic tweets to resume before sunrise.”

4. (Mormonism)The second highest office in the Aaronic priesthood, held by priesthood holders of at least the age of 14.