<p><strong>Noun</strong></p><ul><li>plural fath·oms, (especially collectively) fath·om.</li><li>a unit of length equal to six feet (1.8 meters): used chiefly in nautical measurements.</li></ul><p><strong>Verb</strong></p><ul><li>(used with object) to measure the depth of by means of a sounding line; sound.</li><li>to penetrate to the truth of; comprehend; understand: to fathom someone's motives.</li></ul>