Meaning

• A pronged connecting device which fits into a mating socket, especially an electrical one.

  "I pushed the plug back into the electrical socket and the lamp began to glow again."

• Any piece of wood, metal, or other substance used to stop or fill a hole.

  "Pull the plug out of the tub so it can drain."

• A flat oblong cake of pressed tobacco.

  "He preferred a plug of tobacco to loose chaw."

• A high, tapering silk hat.

• A worthless horse.

  "That sorry old plug is ready for the glue factory!"

• Any worn-out or useless article.

• A block of wood let into a wall to afford a hold for nails.

• A mention of a product (usually a book, film or play) in an interview, or an interview which features one or more of these.

  "During the interview, the author put in a plug for his latest novel."

• A body of once molten rock that hardened in a volcanic vent. Usually round or oval in shape.

  "Pressure built beneath the plug in the caldera, eventually resulting in a catastrophic explosion of pyroclastic shrapnel and ash."

• A type of lure consisting of a rigid, buoyant or semi-buoyant body and one or more hooks.

  "The fisherman cast the plug into a likely pool, hoping to catch a whopper."

• A small seedling grown in a tray from expanded polystyrene or polythene filled usually with a peat or compost substrate.

• (jewellery) A short cylindrical piece of jewellery commonly worn in larger-gauge body piercings, especially in the ear.

• A drug dealer.

• A branch from a water-pipe to supply a hose.

Meaning

• To stop with a plug; to make tight by stopping a hole.

  "He attempted to plug the leaks with some caulk."

• To blatantly mention a particular product or service as if advertising it.

  "The main guest on the show just kept plugging his latest movie: it got so tiresome."

• To persist or continue with something.

  "Keep plugging at the problem until you find a solution."

• To shoot a bullet into something with a gun.

• To have sex with, penetrate sexually.

  "I'd love to plug him."