Mardi Gras ( Fat Tuesday ) is a festival held the day before Ash Wednesday , signifying the end of the Carnival season and the start of Lent . The terms `` Mardi Gras '' , `` Mardi Gras season '' , and `` Carnival season '' , in English , refer to events of the Carnival celebrations , beginning on or after Epiphany and culminating on the day before Ash Wednesday . Mardi Gras is French for `` Fat Tuesday '' ( in ethnic English tradition , Shrove Tuesday ) , referring to the practice of the last night of eating richer , fatty foods before the ritual fasting of the Lenten season , which begins on Ash Wednesday .