Definition of fathom in English:

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Pronunciation: /ˈfaT͟Həm/


A unit of length equal to six feet (approximately 1.8 m), chiefly used in reference to the depth of water: sonar says that we’re in eighteen fathoms
More example sentences
  • If your boat is in the water and cannot be trailered, move it offshore to waters over 200 fathoms deep as soon as a Tsunami Warning is declared.
  • He is still miles and fathoms and nautical miles and light years ahead of everyone else in baseball.
  • On March 23, 1875, 13 days after leaving Nares Harbor, soundings indicated a depth of 4,475 fathoms or about 27,000 feet.


[with object]
1 [usually with negative] Understand (a difficult problem or an enigmatic person) after much thought: he could scarcely fathom the idea that people actually lived in Las Vegas [with clause]: he couldn’t fathom why she was being so anxious
More example sentences
  • I just can't fathom people who could have a quiet life, who don't have to be controversial for a living, but do it anyway.
  • You can analyze a Mozart piano concerto note by note and still not fathom the genius of the whole piece.
  • But I can't fathom anyone reading stories like this and not feeling the sting and burn of utter, abject shame.
understand, comprehend, work out, make sense of, grasp, divine, puzzle out, get to the bottom of;
interpret, decipher, decode
informal make head(s) or tail(s) of, crack
2Measure the depth of (water): an attempt to fathom the ocean
More example sentences
  • In the middle of this temple complex, there is an ancient pond, fed by the waters sprouting from its bed; it has been claimed that the depth of this pond has never been fathomed.
measure the depth of, sound, plumb



Pronunciation: /ˈfaT͟H(ə)məb(ə)l/
Example sentences
  • It was her view that you couldn't fathom policy until the policymakers were made fathomable.
  • Such developments may initially be unusable, only fathomable to geeks.
  • Less fathomable are his attempts to justify his growing disenchantment with the job.


Old English fæthm. The original sense was 'something that embraces', (plural) 'the outstretched arms'; hence, a unit of measurement based on the span of the outstretched arms, later standardized to six feet.

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Syllabification: fath·om

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