tumbler (Noun) — A gymnast who performs rolls and somersaults and twists etc..
tumbler (Noun) — A glass with a flat bottom but no handle or stem; originally had a round bottom.
tumbler (Noun) — A movable obstruction in a lock that must be adjusted to a given position (as by a key) before the bolt can be thrown.
tumbler (Noun) — Pigeon that executes backward somersaults in flight or on the ground.