plural of fuse plug

(aviation) A component of an aircraft wheel held in place by a metal alloy with a low melting point, such that, if the wheel is severely overheated (for instance, by heavy braking), pressure is released from the wheel and tire/tyre in a controlled manner rather than risking an explosion of the wheel assembly.

A small mudhole used for washing out a steam boiler, usually screwed into a taper thread, rather than being held by clamps.

plural of washout plug

Alternative form of not worth a plug nickel

(chiefly US, idiomatic) Having no or almost no value; worthless.