Emily Dickinson Lexicon

FATH'OM, n. [Sax. fæthem; Ir. fead; G. faden; D. vadem. Qu. Dan. favn. The German word signifies a thread, a fathom, and probably thread or line is the real signification.]

1. A measure of length containing six feet, the space to which a man may extend his arms; used chiefly at sea for measuring cables, cordage, and the depth of the sea in sounding by a line and lead.
2. Reach; penetration; depth of thought or contrivance. Shak.