Definition of side cupboard in US English:

side cupboard

noun

  • 1A side table or other item of dining-room furniture (originally) used to hold food and drink ready to be served at table or (later usually) for storing and displaying tableware.

  • 2Generally any cupboard positioned to one side of a room, fixture, etc., or set into a wall, the side of an object, etc.

Origin

Mid 16th century; earliest use found in Hugh Rhodes (fl. ?1545), writer on education.