fathom
Americannoun
-
fathoms,
plural
-
fathom
plural
verb (used with object)
-
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
-
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:
It’s almost hard to fathom how any other individual could surpass his wealth, barring some company-specific problem.
From MarketWatch ● Oct. 6, 2026
Whenever he seems confused, I’m delighted; it’s reassuring to see someone so smart still struggle to fathom this thing of ours.
From The Wall Street Journal ● Sep. 15, 2026
"I think the next generation just can't fathom what actually transpired and how someone could be impacted by that, and so I actually find them asking more questions," he told AFP.
From Barron's ● Sep. 11, 2026
If I—a single woman who lives alone and works from home—don’t have the luxury of me time, I cannot fathom what families, gig workers, and recent college graduates must endure.
From Slate ● Sep. 6, 2026
Kamen could not fathom how Lawrence expected to be immune from courtroom questioning; he supposed, undoubtedly correctly, that Ernest was “not prepared to undergo the trauma of an adversary confrontation.”
From "Big Science" by Michael Hiltzik
DaCosta fathoms the deepest notes in Ibsen’s classic as though they were whale song, remixing them into her own ode to a woman who needs healthier hobbies.
From Los Angeles Times ● Mar. 10, 2026
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
I feel like I'm standing on the top of a bell tower, staring at the ground forty fathoms below.
From "The Inquisitor's Tale" by Adam Gidwitz
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
Where this has led could be fathomed at the Ojai Festival in June.
From Los Angeles Times ● Sep. 6, 2025
"We never fathomed it would be this catastrophic and apocalyptic."
From BBC ● Jan. 14, 2025
This is all so much more than Evans, 36, and Schonberger, 39, could have fathomed when the idea was born almost a decade ago.
From New York Times ● Apr. 3, 2023
My difficulty was further compounded by the fact that for some years my father and I had tended - for some reason I have never really fathomed - to converse less and less.
From "The Remains of the Day" by Kazuo Ishiguro
While James is a good-looking, good-natured young man, he's rather lost when it comes to fathoming the way Pünd can unravel mysteries.
From Salon ● Oct. 31, 2022
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
“I just have a hard time fathoming why a deputy sheriff, or any police officer, would engage in that kind of conduct,” said J.P.
From Los Angeles Times ● Dec. 14, 2019
He was also being “completely honest,” baring a bewildered and troubled soul, not fathoming why he is so uninspired to play a sport he intends, or hopes, to continue on with.
From New York Times ● Jul. 4, 2017
Down, deeper than the fathoming of his eyes, plunged his spirit, and walked the sea's mysteries in vain imaginings.
From The Unknown Sea by Clemence Housman
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Get a wordDefinitions 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.
