plug (Noun) — Blockage consisting of an object designed to fill a hole tightly.
plug (Noun) — A wad of something chewable as tobacco.
plug (Noun) — Blatant or sensational promotion.
plug (Noun) — Electrical device that fits into the cylinder head of an internal-combustion engine and ignites the gas by means of an electric spark.
plug (Noun) — An electrical device with two or three pins that is inserted in a socket to make an electrical connection.
plug (Noun) — An upright hydrant for drawing water to use in fighting a fire.
plug (Noun) — An old or over-worked horse.
plug (Noun) — (fishing) a type of lure consisting of a rigid, buoyant or semi-buoyant body and one or more hooks.
plug (Verb) — Fill or close tightly with or as if with a plug. ex. "plug the hole"
plug (Verb) — Persist in working hard. ex. "Students must plug away at this problem"
plug (Verb) — Deliver a quick blow to. ex. "he plugged me in the stomach"
plug (Verb) — Advertise; praise the qualities of something in order to sell or promote.
plug (Verb) — Insert a plug into. ex. "plug the wall"
plug (Verb) — Insert as a plug. ex. "She plugged a cork in the wine bottle"