fathom
Americannoun
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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
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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:
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
He complained to some that Washington never spoke, was hard to fathom, that his mind seemed busy.
From The Wall Street Journal ● Jun. 26, 2026
“It’s hard to fathom that you’re watching the exploding d— and driving through whales, and you’re like, ‘Wow, this really feels threatening to us in any political way,’” Kripke says.
From Los Angeles Times ● Jun. 10, 2026
But even they came around faster than the burgeoning class of prestige TV era viewers who couldn’t fathom that the new “Battlestar” could be as culturally resonant as, say, “The Sopranos” or “The Wire.”
From Salon ● May 5, 2026
His father, Gaston, had hesitated, looking suddenly stricken for reasons Bobby could not fathom, but finally said he would send him the addresses later, if the crew really went to Europe.
From "The Boys in the Boat: Nine Americans and Their Epic Quest for Gold at the 1936 Berlin Olympics" by Daniel James Brown
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
‘About, well’ — he stood for a moment measuring it with his eyes — ‘about eighteen fathoms, I should guess. Not more.’
From "The Two Towers" 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
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
She’d always known the punishment for what she’d done was going to be bad, but this was far worse than anything she could have fathomed.
From "Beasts of Prey" by Ayana Gray
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
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
Medvedev had difficulty fathoming that he’d have to win the Australian Open every year until he was 34 to match Djokovic’s success there.
From Los Angeles Times ● Feb. 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
She certainly did interest herself very much with lovers, fathoming all the little mysteries of their love-quarrels, and setting every thing quite straight, even when they seemed in inextricable confusion.
From Graham's Magazine Vol XXXIII No. 4 October 1848 by Various
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.
