yellow card

Meanings

1. 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.
2. one of various yellow-colored cards used to verify the healthiness, vaccination status or other medical info of travelers.
3. a form to record safety concerns and adverse reactions to medicinal drugs.
4. A card sent out by a travelling dance or theatre company to request temporary personnel from a local labor union.
5. A yellow ticket.
6. a card given to British Army personnel during The Troubles.