Definition of rap-tap in US English:

rap-tap

(also rap-a-tap)

noun

  • A sharp rapping or tapping sound, as produced by knocking on a door, hammering, etc.

exclamation

  • Representing this sound.

verb

  • no object To make a rapping sound, as on a door, etc.

Origin

Mid 18th century; earliest use found in Charles Johnson (?1679–1748), playwright and poet. From rap + tap. Compare later rap-tap<br>mid 19th century; earliest use found in Edward Capern (1819–1894), poet. From rap + tap, after rap-tap.