noun: (sports) a yellow-coloured card, shown to a player (especially in association football) as a caution that he or she has committed a flagrant foul; a further such foul would result in a red card.
noun: (medicine) one of various yellow-colored cards used to verify the healthiness, vaccination status or other medical info of travelers.
noun: (medicine, UK) a form to record safety concerns and adverse reactions to medicinal drugs.
noun: (often attributive) A card sent out by a travelling dance or theatre company to request temporary personnel from a local labor union.
noun: (historical) A yellow ticket.
noun: (historical) a card given to British Army personnel during The Troubles .