in·sti·tu·tor \-üd.ə(r), -ütə-\noun (-s) Etymology: Latin, from institutus (past participle) + -or : one that institutes: as a.: founder, ordainer, establisher < the institutor of this pleasant custom > b.archaic: teacher, instructor c.: a Protestant Episcopal bishop or a priest delegated by him who institutes a rector or assistant minister into a parish or church