fathom
     n 1: a linear unit of measurement (equal to 6 feet) for water
          depth [syn: {fthm}]
     2: (mining) a unit of volume (equal to 6 cubic feet) used in
        measuring bodies of ore [syn: {fthm}]
     v 1: come to understand [syn: {penetrate}, {bottom}]
     2: measure the depth of (a body of water) with a sounding line
        [syn: {sound}]
Source: WordNet® 2.0