5. A block of wood let into a wall, to afford a hold for nails. Fire plug, a street hydrant to which hose may be attached. Hawse plug, a tapering valve, which turns in a case like the plug of a faucet.
Origin: Akin to D. Plug, G. Pflock, Dan. Plok, plug, Sw. Plugg; cf. W. Ploc.