(1):

(v. i.) To hold a wassail; to carouse.

(2):

(n.) An occasion on which such good wishes are expressed in drinking; a drinking bout; a carouse.

(3):

(n.) The liquor used for a wassail; esp., a beverage formerly much used in England at Christmas and other festivals, made of ale (or wine) flavored with spices, sugar, toast, roasted apples, etc.; - called also lamb's wool.

(4):

(n.) A festive or drinking song or glee.

(5):

(a.) Of or pertaining to wassail, or to a wassail; convivial; as, a wassail bowl.

(6):

(n.) An ancient expression of good wishes on a festive occasion, especially in drinking to some one.