Possible Definitions:
1. Plug (n.) Any piece of wood, metal, or other substance used to stop or fill a hole; a stopple.
2. Plug (n.) A flat oblong cake of pressed tobacco.
3. Plug (n.) A high, tapering silk hat.
4. Plug (n.) A worthless horse.
5. Plug (n.) A block of wood let into a wall, to afford a hold for nails.
6. Plug (v. t.) To stop with a plug; to make tight by stopping a hole.