From Middle English fathome, fadome, from Old English fæþm, fæþme (“outstretched or encircling arms, embrace, grasp, protection, interior, bosom, lap, breast, womb, fathom, cubit, power, expanse, surface”), from Proto-Germanic *faþmaz (“embrace”), from Proto-Indo-European *pet- (“to spread out, extend”). Cognate with Low German fadem, faem (“a cubit, thread”), Dutch vadem, vaam (“fathom”), German Faden (“thread, filament, fathom”), Danish favn (“embrace, fathom”), Swedish famn (“the arms, bosom, embrace”), Icelandic faðmur (“embrace”).
fathom (plural fathoms)
- (obsolete) Grasp, envelopment, control.
- (nautical) A measure of length corresponding to the outstretched arms, standardised to six feet, now used mainly for measuring depths in seas or oceans.
- (by extension) Mental reach or scope; penetration; the extent of capacity; depth of thought or contrivance.
- Another of his fathom they have none / To lead their business (Othello, I.i. 151-2).
- (measure of length corresponding to the outstretched arms): brace
- (transitive, archaic) To encircle with outstretched arms, especially to take a measurement; to embrace.
- (transitive) To measure the depth of, take a sounding of.
- (transitive, figuratively) To get to the bottom of; to manage to comprehend (a problem etc.).
- I can't for the life of me fathom what this means.