Merriam-Webster Collegiate Dictionary - brad

 I. noun  Etymology: Middle English, from Old Norse broddr spike; perhaps akin to Old English byrst bristle — more at bristle  Date: 13th century  1. a thin nail of the same thickness throughout but tapering in width and having a slight projection at the top of one side instead of a head  2. a slender wire nail with a small barrel-shaped head  II. transitive verb  (~ded; ~ding)  Date: 1794 to fasten with ~s