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
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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:
If you can’t fathom forking over hundreds of dollars a night, or more, for a hotel, this is yet another reason the premium cards probably aren’t right for you.
From The Wall Street Journal ● Sep. 30, 2026
Evan Mawarire is a Zimbabwean pastor and activist, and since 2008, his home country has experienced a kind of inflation and economic instability that is hard to fathom.
From Slate ● Sep. 20, 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
The only solution Owens and Austin Baurichter could fathom then was creating a ballot measure.
From Salon ● Jul. 9, 2026
I couldn’t even fathom how much that would be.
From "Hattie Big Sky" by Kirby Larson
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
You know those deep-sea fish dragged by nets from fathoms of blackness, how obvious it is that they aren’t supposed to exist where we are?
From New York Times ● Jul. 29, 2020
Rounding the corner they saw before them a low cliff, some five fathoms high, with a broken and jagged top.
From "The Fellowship of the Ring" by J.R.R. Tolkien
Ken Ono’s career as one of the world’s most prominent mathematicians has taken him to places that he never could have fathomed.
From The Wall Street Journal ● Dec. 4, 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
“He did something she could have never anticipated or fathomed or predicted,” Ms. Smith said.
From New York Times ● Jan. 25, 2024
The thing she’d wanted, the thing she dreamed of, belonged to her and was better than anything she could have fathomed.
From "Night Owls" by A.R. Vishny
Climate change is what philosopher Timothy Morton calls a hyperobject: something that so massively occupies space and time that our puny primate brains have trouble fathoming them.
From Salon ● Dec. 31, 2025
But fathoming other universes is the essence of Theo’s job.
From Washington Post ● Sep. 21, 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
She glanced at him with a startled look, fathoming his grim thought instantly, and it blanched her face for a moment.
From Maid of the Mist by John Oxenham
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.
