fishmouth

Noun

 * 1)  A half-cylindrical or half-conical shaped opening or void in a lapped edge or seam, usually caused by wrinkling or shifting of ply sheets during installation.
 * 2)  A wide incision made to drain fluid from under the fingernail.
 * 3)  A horizontal incision on the breast aligned with the nipples made to drain or excise the breast fat as a form of top surgery.
 * 4)  A chronically open mouth.