fishmouth

noun4

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. •
   (informal) A chronically open mouth.