1. Shrove Tuesday: the day when traditionally all fat and meat in the house were finished up, before Christians were banned from eating them during Lent, which commenced the following day on mercredi des Cendres (usually uncountable)

2. Mardi Gras: the last day of a carnival, traditionally the celebration immediately before the start of Lent when joy could be out of place for Christians (usually uncountable)

3. a person dressed up in a ridiculous disguise (countable)