noun
plural buns
[count] :a small, round or long bread for one person to eat
[count] :a small, usually round sweet cake
[count] :a way of arranging long hair by twisting it into a round shape at the sides or back of the head
buns [plural] US informal :the two soft parts of the body that you sit on :buttocks
have a bun in the oven
informal :to be pregnant
US