Definition of muffins:
(n) :
A cupcake-shaped baked good (for example of cornbread, banana bread, or a chocolate dough), sometimes glazed but typically without frosting, eaten especially for breakfast (in contrast to a cupcake, which is a dessert).
(n) :
(British) A type of flattish bun, usually cut in two horizontally, toasted and spread with butter, etc., before being eaten.
(n) :
(colloquial, endearing) Term of endearment.
(n) :
(baseball, slang) A less talented player; one who muffs, or drops the ball.
(n) :
(vulgar, slang) The vulva or vagina; pubic hair around it.
(v) :
(intransitive) To become like a muffin; to increase in size.