TUMBLER

noun Date: 14th century one that tumbles: as, one who performs tumbling feats ; acrobat , any of various domestic pigeons that tumble or somersault backward in flight or on the ground, a drinking glass without foot or stem and originally with pointed or convex base, 3. a movable obstruction in a lock (as a lever, latch, wheel, slide, or pin) that must be adjusted to a particular position (as by a key) before the bolt can be thrown, a piece on which the mainspring acts in a gun's lock, a device or mechanism for tumbling (as a revolving cage in which clothes are dried), a worker who operates a ~, ~ful noun