Lug n.
 1. The ear, or its lobe. [Scot. & Prov. Eng.]
 2. That which projects like an ear, esp. that by which anything is supported, carried, or grasped, or to which a support is fastened; an ear; as, the lugs of a kettle; the lugs of a founder's flask; the lug (handle) of a jug.
 3. Mach. A projecting piece to which anything, as a rod, is attached, or against which anything, as a wedge or key, bears, or through which a bolt passes, etc.
 4. Harness The leather loop or ear by which a shaft is held up.
 5. Zool. The lugworm.
 Lug bolt Mach., a bolt terminating in a long, flat extension which takes the place of a head; a strap bolt.
 Lug nut Mach., a large nut fitting a heavy bolt; -- used especially of the nuts used to attach wheels to vehicles.
 Lug wrench Mach., a wrench used to tighten or loosen lug nuts, usually a steel rod having a hexagonally shaped socket which fits closely over the lug nut; sometimes in the shape of a cross, having several such sockets, one at the end of each arm, to accommodate nuts of different sizes.