pink slip

Definition from Nolo’s Plain-English Law Dictionary

1) Slang for notice from an employer that one is being fired or laid off. 2) Slang for the official title certificate to a vehicle, because in some states the document is or was pink. This is the source of the phrase "racing for pinks," when the winner of a car race wins ownership of the loser's car.

Definition provided by Nolo’s Plain-English Law Dictionary.