1a piece of solid material fitting tightly into a hole and blocking it up:somewhere in the pipes there is a plug of ice blocking the flow
a circular piece of metal, rubber, or plastic used to stop the plughole of a bath or basin and keep the water in it:she pulled out the plug and got out on to the sodden bath mat
North American informal a baby’s dummy.
a mass of solidified lava filling the neck of a volcano.
(in gardening) a young plant or clump of grass with a small mass of soil protecting its roots, for planting out.
2a device for making an electrical connection between an appliance and the mains, consisting of an insulated casing with metal pins that fit into holes in a socket:the cable is fitted with a two-pin plug
a socket into which an electric plug can be fitted:the vacuum cleaner cord snaked away to a hidden plug