1. To start or advance a course of action, a policy, a program, a rule: The school decided to institute new regulations for safety on the playground.
2. To assign a person to a position: Mrs. Gibson instituted her lawyer, Mrs. Timmons, to be her executrix and to take care of her will.
3. To begin judicial procedures in court: Because the tenant hadn't been paying rent for many months, the owner of the apartment instituted an eviction process in law court.