Fĭd, n.

noun

n. [Prov. Eng. fid, a small, thick lump.]

(Naut.) A square bar of wood or iron, used to support the topmast, being passed through a hole at its heel, and resting on the trestle-trees. Totten.
A wooden or metal bar or pin, used to support or steady any thing.
A pin of hard wood, tapering to a point, used to open the strands of a rope in splicing.