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”), Norwegian Bokmål favn (“embrace, fathom”), Swedish famn (“the arms, bosom, embrace”), Icelandic faðmur (“embrace”), Latin pateō, Ancient Greek πετάννυμι (petánnumi), Ancient Greek πέταλος (pétalos) [whence English petal].
fathom (plural fathoms)
- (obsolete) Grasp, envelopment, control.
- (units of measure, now usually nautical) An English unit of length for water depth notionally based upon the width of grown man's outstretched arms but standardized as 6 feet (about 1.8 m).
- (units of measure) Various similar units in other systems.
- (figuratively) Depth of insight, mental reach or scope.
- (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; understand (a problem etc.).
- Synonyms: fathom out, figure out, puzzle out, work out
- I can't for the life of me fathom what this means.