noun

• (electricity) 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."
• (electricity) A pronged connecting device which fits into a mating socket, especially an electrical one.
• (US) A flat oblong cake of pressed tobacco.
  "He preferred a plug of tobacco to loose chaw."
• (US, slang) A high, tapering silk hat.

verb

• (transitive) To stop with a plug; to make tight by stopping a hole.
  "He attempted to plug the leaks with some caulk."
• (transitive) To promote (something, especially a product or service); to mention (something) as if promoting or advertising it.
  "The main guest on the show just kept plugging his latest movie: it got so tiresome."
• (intransitive, informal) To persist or continue with something.
  "Near-synonym: plug away"
• (transitive, slang) To shoot (someone) with a bullet.
  "1884, H. Rider Haggard, The Witch's Head I am awfully glad that you kept your nerve and plugged him; it would have been better if you could have nailed him through the right shoulder, which would not have killed him..."