Emily Dickinson Lexicon

BRAD, n. [Arm. broud, a point; Ir. brod, or braid; Dan. braad, a goad or sting; Ch. ברט barat, a dart, a borer.]

A particular kind of nail used in floors and other work, where it is deemed proper to drive nails entirely into the wood. For this purpose, it is made without a broad head or shoulder over the shank. – Moxon.