/tum"bleuhr/ , n.
1. a person who performs leaps, somersaults, and other bodily feats.
2. (in a lock) any locking or checking part that, when lifted or released by the action of a key or the like, allows the bolt to move.
3. a stemless drinking glass having a flat, often thick bottom.
4. (in a gunlock) a leverlike piece that by the action of a spring forces the hammer forward when released by the trigger.
5. Mach.
a. a part moving a gear into place in a selective transmission.
b. a single cog or cam on a rotating shaft, transmitting motion to a part with which it engages.
6. a tumbling box or barrel.
7. a person who operates a tumbling box or barrel.
8. one of a breed of dogs resembling a small greyhound, used formerly in hunting rabbits.
9. Also called roller . one of a breed of domestic pigeons noted for the habit of tumbling backward in flight.
10. a toy, usually representing a fat, squatting figure, that is weighted and rounded at the bottom so as to rock when touched.
11. a tumbrel or tumble cart.
[ 1300-50; ME: acrobat; see TUMBLE, -ER 1 . Compare LG tümeler drinking-cup, kind of pigeon ]