Fathom

How to spell fathom

6 letters · 2 syllables

How to pronounce fathom

Say the part in capitals loudest.

What does fathom mean?

1. verbTo come to understand something difficult or puzzling after careful thought.
2. nounA nautical unit of depth equal to six feet, used chiefly for measuring water.

Fathom in a sentence

• verb

  She could not fathom why the invoice had been paid twice.

• noun

  The chart marked the wreck at a depth of one fathom.

• verb

  Engineers struggled to fathom the cause of the recurring fault.

• noun

  Each fathom on the sounding line was marked with a knot.

Where does fathom come from?

Language of origin: Germanic

This is a thoroughly native English word, descending from the Old English fæthm, which literally meant the outstretched or encircling arms, and by extension an embrace or the breadth a person could span with both arms held wide. Because that arm-span measured roughly six feet, the word came to name a unit of length, and sailors in particular adopted it for sounding the depth of water, lowering a knotted line and counting the fathoms. The figurative verb 'to fathom', meaning to get to the bottom of something or finally understand it, grew naturally out of this practice of measuring how deep the water really was. The word has Germanic cousins, such as the Dutch vadem and the German Faden, all tracing back to a root meaning to stretch out or spread. The 'th' spelling preserves the old soft consonant of fæthm, and the silent-feeling, unstressed second syllable ending in '-om' rather than '-um' is the main thing writers have to remember.

How the word is built

• fathom (whole word, from Old English fæthm: the span of a person's outstretched arms)