Bat (băt), n. [OE. batte, botte, AS. batt; perhaps fr. the Celtic; cf. Ir. bat, bata, stick, staff; but cf. also F. batte a beater (thing), wooden sword, battre to beat.]
1. A large stick; a club; specifically, a piece of wood with one end thicker or broader than the other, used in playing baseball, cricket, etc.
2. (Mining) Shale or bituminous shale. Kirwan.
3. A sheet of cotton used for filling quilts or comfortables; batting.
4. A part of a brick with one whole end.
Bat bolt(Machinery), a bolt barbed or jagged at its butt or tang to make it hold the more firmly. Knight.