n. & v.
--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 f{aelig}thm outstretched arms f. Gmc