Definition of master card in English:

master card

noun

  • 1Bridge and Whist. A card that cannot be beaten unless it is trumped.

  • 2A record card which summarizes the information recorded on a number of other cards.

  • 3In form MasterCard. A trademark for: a brand of credit card.

Origin

Late 19th century; earliest use found in Appletons' Journal. From master + card.