fathom
Americannoun
-
fathoms,
plural
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fathom
plural
verb (used with object)
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fathoms,
present (3rd person singular)
-
fathomed,
past participle, past
-
fathoming
present participle
-
to measure the depth of by means of a sounding line; sound.
-
to penetrate to the truth of; comprehend; understand.
to fathom someone's motives.
noun
-
a unit of length equal to six feet (1.829 metres), used to measure depths of water
-
mining a unit of volume usually equal to six cubic feet, used in measuring ore bodies
-
forestry a unit of volume equal to six cubic feet, used for measuring timber
verb
-
to measure the depth of, esp with a sounding line; sound
-
to penetrate (a mystery, problem, etc); discover the meaning of
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Participles
Conjugated Forms
Present
-
fathomsimple
-
fathomssimple
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have fathomedperfect
-
has fathomedperfect
-
am fathomingprogressive
-
are fathomingprogressive
-
is fathomingprogressive
-
have been fathomingperfect progressive
-
has been fathomingperfect progressive
Past
-
fathomedsimple
-
had fathomedperfect
-
was fathomingprogressive
-
were fathomingprogressive
-
had been fathomingperfect progressive
Future
Etymology
Origin of fathom
First recorded before 900; Middle English fathme, Old English fæthm “span of outstretched arms”; cognate with German Faden “six-foot measure,” Old Norse fathmr; akin to Latin patēre “to stand open” ( see patent)
Explanation
To fathom something is to understand it thoroughly. It's usually used in the negative, as in "I can't fathom why he doesn't want to go along with us." Fathom is from Middle English fadme, from Old English fæthm, "outstretched arms." The Old English and modern English noun also refers to a unit of length used to measure the depth of water. The sense of intellectual depth comes from that meaning — to understand or fathom something thoroughly is "to get to the bottom of it."
Vocabulary lists containing fathom
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
The experience suggests that to achieve enlightenment, one must embrace these limitations, come to peace with contradictions, and maintain faith in a larger order that we cannot fathom.
From The Wall Street Journal ● Jul. 31, 2026
An MSP called Sarwar's decision "bizarre", while a senior Scottish Labour MP said it was "absolutely mad. I cannot begin to fathom the logic of it."
From BBC ● Jul. 21, 2026
The only solution Owens and Austin Baurichter could fathom then was creating a ballot measure.
From Salon ● Jul. 9, 2026
But during a week when the canted economy just created its first trillionaire, I can’t fathom why Sarnoski felt we needed this version of Robin Hood now.
From Los Angeles Times ● Jun. 18, 2026
But at the last moment Mia had burned the prints and negatives, for reasons even Pearl could not fathom.
From "Little Fires Everywhere" by Celeste Ng
But “Clarence” is also heartbreakingly sincere, with some serious plumbing of faith, commentary on systems of oppression and fathoms of emotion in Stanfield’s virtuosic double performance.
From Los Angeles Times ● Jan. 10, 2024
In the late 1800s the Yup’ik people from the Alaskan coast recorded building kayaks that were 2.5 fathoms long plus a cockpit, which was the length of an arm with a closed fist.
From Science Magazine ● May 31, 2023
“He’s playing it off. I don’t think he fathoms how bad this is. Shame on him. I hope he gets what he deserves.”
From Washington Times ● Jul. 6, 2021
And after some initial tests in the shallow water, the Thresher headed out to where the ocean was 1,400 fathoms, or a mile and half, deep.
From Washington Post ● Sep. 26, 2019
In the daylight, the water was clear enough to see fathoms beneath the surface.
From "The Line Tender" by Kate Allen
Ken Ono’s career as one of the world’s most prominent mathematicians has taken him to Hollywood and the Olympics, places that he never could have fathomed.
From The Wall Street Journal ● Dec. 7, 2025
"We never fathomed it would be this catastrophic and apocalyptic."
From BBC ● Jan. 14, 2025
Gmail’s existence is also why other free email services and the internal email accounts that employees use on their jobs offer far more storage than was fathomed 20 years ago.
From Seattle Times ● Mar. 31, 2024
Brandishing a competitive nature and an extreme love of live entertainment, TV and movies since childhood, she never could have fathomed that a blend of all of those attributes could equate to a job.
From Los Angeles Times ● Mar. 7, 2024
Had she had all her wits, Desdemona could not possibly have fathomed what I was saying.
From "Middlesex: A Novel" by Jeffrey Eugenides
I truly have a hard time fathoming that.
From Salon ● Oct. 16, 2022
Now, though some of the references have become more obscure with time, it’s hard to imagine anyone not fathoming the play’s gist.
From New York Times ● May 7, 2021
They are like the proverbial worker who knows how to use a hammer and thus sees everything as a nail—not fathoming the existence of other tools.
From Scientific American ● Jun. 8, 2020
What would be as a story beyond fathoming for the second-grade class Lieberg will teach Monday back home in Helena, Mont., became something nevertheless inspiring.
From Los Angeles Times ● Mar. 18, 2018
Fully convinced that behind that which was visible at the Francoise hovel, lay a mystery, Vernet resolved upon fathoming that mystery, and he set to work with rare vigor.
From Dangerous Ground or, The Rival Detectives by Lawrence L. Lynch
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
