yellow cards

Noun

yellow card (plural yellow cards)

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. (UK) A form to record safety concerns and adverse reactions to medicinal drugs.
4. (attributive, often) A card sent out by a travelling dance or theatre company to request temporary personnel from a local labor union.
   • Some large modern dance companies, most large ballet companies, and most large theater companies also require union crews. These are called yellow card companies.1991, M. Kay Barrell, The technical production handbook
5. (historical) A yellow ticket.
6. (historical) A card given to British Army personnel during The Troubles.