noun
Colloquial word for the side of the body or an object, often with a slightly rough or informal feel. Compare with the more neutral 横腹.
See also: 横腹
転んで横っ腹を打った。
I fell and hit my side.
彼は笑いすぎて横っ腹が痛くなった。
He laughed so much that his sides hurt.
横腹 is the standard, neutral term for 'side/flank'. 横っ腹 is a more colloquial variant with a rougher nuance.
Formed from 横 (side) + 腹 (belly) with the colloquial infix っ, giving a casual, emphatic feel.