—n. (pl. often fathom when prec. by a number)
1 a measure of six feet, esp. used in taking depth soundings.
2 Brit. a quantity of wood six feet square in cross-section.
—v.tr.
1 grasp or comprehend (a problem or difficulty).
2 measure the depth of (water) with a sounding-line.
Derivatives:
fathomable adj. fathomless adj.
Etymology: OE faeligthm outstretched arms f. Gmc
Useful english dictionary. 2012.