noun

• One who makes a tapping noise.
• A tap-dancer.
• A phone tapper or wiretapper.
• (baseball slang) A weakly hit ground ball.
• (telegraphy) In early wireless telegraphs, a device used to shake loose the filings of a coherer.
• (Britain, dialect) The lesser spotted woodpecker.
• (US) A tapster.
• (sports) An assistant in the sport of paraswimming who taps blind or visually impaired swimmers with a pole to indicate when they should turn around.
• A surname originating as an occupation for an innkeeper or wine merchant.