tumbler

noun

• 1a drinking glass with straight sides and no handle or stem.

  [formerly having a rounded bottom so as not to stand upright]

• 2an acrobat, especially one who performs somersaults.
• a pigeon of a breed that repeatedly turns over backwards in flight.

• 3 (also tumbler dryer) a tumble dryer.

• 4a pivoted piece in a lock that holds the bolt until lifted by a key.
• a notched pivoted plate in a gunlock.

• 5an electrical switch worked by pushing a small sprung lever.

• 6another term for tumbling barrel.