Real Dictionary

drum
countable noun: A drum is a circular object on which wire or rope is wound and kept.
countable noun: A drum is a hollow cylindrical structure which is part of a machine, for example a washing machine.
countable noun: A drum is a large cylindrical container which is used to store fuel or other substances.
countable noun: A drum is a musical instrument consisting of a skin stretched tightly over a round frame. You play a drum by beating it with sticks or with your hands.
verb: If something drums on a surface, or if you drum something on a surface, it hits it regularly, making a continuous beating sound.

drum in American English 1
a percussion instrument consisting of a hollow cylinder or hemisphere with a membrane stretched tightly over the end or ends, played by beating with the hands, sticks, etc.
to beat a drum

drum in American English 2
a narrow hill or ridge
noun: a long, narrow hill or ridge

drum in American Englishesp collectively for 11 1
noun: a musical percussion instrument consisting of a hollow, usually cylindrical, body covered at one or both ends with a tightly stretched membrane, or head, which is struck with the hand, a stick, or a pair of sticks, and typically produces a booming, tappin

drum in British English 1
noun: a percussion instrument sounded by striking a membrane stretched across the opening of a hollow cylinder or hemisphere

drum in British English 2
noun: a narrow ridge or hill

drum in Mechanical Engineering
noun: A drum is a hollow rotating part in a steam turbine or an axial compressor (= a compressor in which gas flows parallel with the rotation of the axis).