a large drinking glass without a handle, orig with a convex base but now flat-bottomed
an acrobat or gymnast
= tumble-dryer
a movable part of a lock, e.g. a lever, wheel, or pin, that must be adjusted to a particular position before the lock can be opened
a spring-operated lever that forces the hammer of a firearm forwards when released by the trigger
the movable part of a reversing or speed-changing gear
= tumbling barrel
any of various domestic pigeons that tumble or somersault backwards in flight or on the ground