Definition of plug

• n. - Any piece of wood, metal, or other substance used to stop or fill a hole; a stopple.
• n. - A flat oblong cake of pressed tobacco.
• n. - A high, tapering silk hat.
• n. - A worthless horse.
• n. - A block of wood let into a wall, to afford a hold for nails.
• v. t. - To stop with a plug; to make tight by stopping a hole.