from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A yellow-colored card shown by a referee to a player, especially in soccer, to indicate that the player has committed a flagrant foul. Being shown two yellow cards results in ejection from the game.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a yellow-coloured card, shown to a player, (especially in association football), as a caution that he has committed a flagrant foul; a further such foul would result in a red card.
Sorry, no etymologies found.