carnival - the season immediately preceding Lent, devoted in Italy and other Roman Catholic countries to revelry and riotous amusement, Shrove-tide; the festivity of this season. High Carnival: the revelry of the Carnival at its height.
Originally (according to Tommaseo and Bellini) ‘the day preceding the first of Lent’; commonly extended to the last three days or the whole week before Lent; in France it comprises Jeudi gras, Dimanche gras, Lundi gras and Mardi gras, i.e. Thursday before Quinquagesima, Quinquagesima Sunday, Monday, and Shrove Tuesday; in a still wider sense it includes ‘the time of entertainments intervening between ‘Twelfth-day’ (or Boxing Day) and Ash Wednesday’ (Littré).