someone who plays a drum
"The drummer started tapping his sticks on the snare to keep time for the rest of the band."
One who plays the drums.
"The police arrested the drummer after he broke into several houses to steal television sets."
A housebreaker.
A surname.
"The famous drummer was actually born under the family name Drummer, but he changed his stage name to sound more musical."
The word drummer is formed by combining the root word drum with a suffix that indicates someone who performs an action. It originally referred to a person who plays the instrument, a meaning it retains in modern English.