Defn: The upper horizontal part of a step, on which the foot is placed.
6. (Fort.)
Defn: The top of the banquette, on which soldiers stand to fire over the parapet.
7. (Mach.) (a) The part of a wheel that bears upon the road or rail. (b) The part of a rail upon which car wheels bear.
8. (Biol.)
Defn: The chalaza of a bird's egg; the treadle.
9. (Far.)
Defn: A bruise or abrasion produced on the foot or ankle of a horse that interferes. See Interfere, 3.
TREADBOARD
Tread"board`, n. [Arch.]
Defn: See Tread, n., 5.