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fath·​om ˈfa-t͟həm How to pronounce fathom (audio)
: a unit of length equal to six feet (1.83 meters) used especially for measuring the depth of water
sometimes used in the singular when qualified by a number
five fathom deep
: comprehension
the themes display a newer fathom than the technical modernism of the composer's earlier worksNewsweek


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fathomed; fathoming; fathoms

intransitive verb

: probe
: to take soundings

transitive verb

: to measure by a sounding line
: to penetrate and come to understand
couldn't fathom the problem
fathomable adjective

Did you know?

Did fathom Always Refer to a Measurement?

Fathom comes from the Old English word fæthm, meaning "outstretched arms." The noun fathom, which now commonly refers to a measure (especially of depth) of six feet, was originally used for the distance, fingertip to fingertip, created by stretching one's arms straight out from the sides of the body. In one of its earliest uses, the verb fathom was a synonym of our modern embrace: to fathom someone was to encircle the person with your arms. By the 1600s fathom had taken to the seas, with the verb being used to mean "to measure by a sounding line." At the same time, the verb also developed senses synonymous with probe and investigate, and it is now frequently used to refer to the act of getting to the bottom of something, figuratively speaking.

Examples of fathom in a Sentence

Noun The water here is five fathoms deep. Verb the pilot had to continually fathom the river, which drought conditions had lowered to unprecedented levels
Recent Examples on the Web
In Zones 1 and 2 (Mendocino, Humboldt and Del Norte counties), crabbing may continue, though officials are limiting fishermen to a depth restriction of 30 fathoms, about 180 feet. Linda Zavoral, The Mercury News, 28 Mar. 2024 My father laughing like a storm several fathoms under a sea’s surface. Matthew Gavin Frank, Harper's Magazine, 11 May 2022 See all Example Sentences for fathom 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'fathom.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Noun and Verb

Middle English fadme, from Old English fæthm outstretched arms, length of the outstretched arms; akin to Old Norse fathmr fathom, Latin patēre to be open, pandere to spread out, Greek petannynai

First Known Use


before the 12th century, in the meaning defined at sense 1


1607, in the meaning defined at intransitive sense 1

Time Traveler
The first known use of fathom was before the 12th century


Dictionary Entries Near fathom

Cite this Entry

“Fathom.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fathom. Accessed 16 Apr. 2024.

Kids Definition


1 of 2 noun
fath·​om ˈfat͟h-əm How to pronounce fathom (audio)
: a unit of length equal to six feet (about 1.83 meters) used especially for measuring the depth of water


2 of 2 verb
: to measure by a sounding line
: to come to understand
can't fathom why
fathomable adjective

More from Merriam-Webster on fathom

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