Noun

1. One who tumbles; one who plays tricks by various motions of the body; an acrobat.
2. A movable obstruction in a lock, consisting of a lever, latch, wheel, slide, or the like, which must be adjusted to a particular position by a key or other means before the bolt can be thrown in locking or unlocking.
3. A piece attached to, or forming part of, the hammer of a gunlock, upon which the mainspring acts and in which are the notches for sear point to enter.
4. A drinking glass that has no stem, foot, or handle — so called because such glasses originally had a pointed or convex base and could not be set down without spilling. This compelled the drinker to finish his measure.
5. A variety of the domestic pigeon remarkable for its habit of tumbling, or turning somersaults, during its flight.
6. A beverage cup, typically made of stainless steel, that is broad at the top and narrow at the bottom commonly used in India.