from
The Collaborative International Dictionary of English v.0.48
Brad \Brad\, n. [Cf. OE. brod, Dan. braad prick, sting, brodde
ice spur, frost nail, Sw. brodd frost nail, Icel. broddr any
pointed piece of iron or stell; akin to AS. brord point,
spire of grass, and perh. to E. bristle. See {Bristle}, n.]
A thin nail, usually small, with a slight projection at the
top on one side instead of a head; also, a small wire nail,
with a flat circular head; sometimes, a small, tapering,
square-bodied finishing nail, with a countersunk head.
[1913 Webster]