tumbler

Concise Oxford English Dictionary © 2008 Oxford University Press:
tumbler/ˈtʌmblə(r)/

▶noun

• 1 a drinking glass with straight sides and no handle or stem. [formerly having a rounded bottom so that it could not be set down until emptied.]

• 2 an acrobat.

• 3 a tumble dryer.

• 4 a pigeon of a breed that repeatedly turns over backwards in flight.

• 5 a pivoted piece in a lock that holds the bolt until lifted by a key.

  ■ a notched pivoted plate in a gunlock.

• 6 an electrical switch worked by pushing a small sprung lever.

• 7 a tumbling barrel.