know
1 Americanverb (used with object)
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knows,
present (3rd person singular)
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knew,
past
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known,
past participle
-
knowing
present participle
-
to perceive or understand as fact or truth; to apprehend clearly and with certainty.
I know the situation fully.
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to have established or fixed in the mind or memory.
to know a poem by heart; Do you know the way to the park from here?
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to be cognizant or aware of.
I know it.
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be acquainted with (a thing, place, person, etc.), as by sight, experience, or report.
to know the mayor.
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to understand from experience or attainment (usually followed by how before an infinitive).
to know how to make gingerbread.
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to be able to distinguish, as one from another.
to know right from wrong.
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Archaic. to have sexual intercourse with.
verb (used without object)
-
knows,
present (3rd person singular)
-
knew,
past
-
known,
past participle
-
knowing
present participle
-
to have knowledge or clear and certain perception, as of fact or truth.
-
to be cognizant or aware, as of some fact, circumstance, or occurrence; have information, as about something.
noun
idioms
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know the ropes, to understand or be familiar with the particulars of a subject or business.
He knew the ropes better than anyone else in politics.
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in the know, possessing inside, secret, or special information.
noun
verb
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(also intr; may take a clause as object) to be or feel certain of the truth or accuracy of (a fact, etc)
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to be acquainted or familiar with
she's known him five years
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to have a familiarity or grasp of, as through study or experience
he knows French
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(also intr; may take a clause as object) to understand, be aware of, or perceive (facts, etc)
he knows the answer now
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(foll by how) to be sure or aware of (how to be or do something)
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to experience, esp deeply
to know poverty
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to be intelligent, informed, or sensible enough (to do something)
she knew not to go home yet
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(may take a clause as object) to be able to distinguish or discriminate
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archaic to have sexual intercourse with
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I have an idea
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to know how one thing or things in general work
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informal a parenthetical filler phrase used to make a pause in speaking or add slight emphasis to a statement
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things are uncertain
noun
Usage
What are other ways to say know? To know something is to perceive or understand it as fact or truth. When should you use this verb over understand or comprehend? Find out on Thesaurus.com.
Other Word Forms
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
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knowsimple
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knowssimple
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have knownperfect
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has knownperfect
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am knowingprogressive
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are knowingprogressive
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is knowingprogressive
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have been knowingperfect progressive
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has been knowingperfect progressive
Past
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knewsimple
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had knownperfect
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was knowingprogressive
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were knowingprogressive
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had been knowingperfect progressive
Future
Etymology
Origin of know
First recorded before 900; Middle English knowen, knawen, Old English gecnāwan; cognate with Old High German -cnāhan, Old Norse knā “to know how, be able to”; akin to Greek gignṓskein, Latin (g)nōscere, Sanskrit jñātá “known”; see also can 1, gnostic
Explanation
To know something means to have a piece of information or a certain understanding of something. If someone tells you their phone number and you remember it, you know. There's a reason you can find the word know in the word knowledge — to know is to have knowledge about something, to be familiar with an idea, or to recognize someone. If you're "in the know," you have information that is only known to a select group of people. But be careful — to know someone in the Biblical sense means that you're having sexual relations with them.
Vocabulary lists containing know
Words from "Miss Alaineus, A Vocabulary Disaster" by Debra Frasier
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Spelling Practice 1, Unit 3
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Spelling Practice, Unit 8
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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:
“I really don’t know what to make of it because I didn’t put eyes on it,” manager Dave Roberts said before the game.
From Los Angeles Times ● Aug. 28, 2026
After the first-Test win at Headingley, captain Joe Root said his pace bowlers "do not know how good they can be" and praised the variety they offer.
From BBC ● Aug. 28, 2026
"I don't know how people don't recognize how dangerous this predicament is, how dangerous this is for Jews," he said.
From Barron's ● Aug. 28, 2026
“I know a con man when I see one,” says Mr. Rogers, who was a special agent with the FBI from 1989 through 1994.
From The Wall Street Journal ● Aug. 28, 2026
“Ah, no, it’s okay. I know you’re tired. Arlo will bring the food to you. You can stay where you are,” Dad says, trying to sound casual about it.
From "Split the Sky" by Marie Arnold
Sometimes, even when the prosecutor involved almost certainly knows something other than justice is in the works, there is a momentum of ego and bureaucracy that is hard to reverse.
From Los Angeles Times ● Aug. 28, 2026
He knows better than anyone about these things, because he has done it so many times before.
From BBC ● Aug. 27, 2026
“She knows she has it. She knows she’s forgetting things. And this trip was an opportunity to not let the Alzheimer’s matter anymore.”
From The Wall Street Journal ● Aug. 27, 2026
Nobody knows how much further this goes, and anyone who tells you they do know is guessing.
From MarketWatch ● Aug. 27, 2026
“Miss ten Boom, I am a Jew. Who knows when they will come to take me away? My wife too—although she is a Gentile—is in danger because of her marriage.”
From "The Hiding Place" by Corrie ten Boom
“I asked for it because I knew I had done nothing wrong.”
From The Wall Street Journal ● Aug. 29, 2026
"Even the majority of Norwegians who never met you in person still felt like they knew you," Mayor Lindboe added in her tribute.
From BBC ● Aug. 28, 2026
The wunderkind coach knew he was inheriting a football program in a years-long slump.
From Los Angeles Times ● Aug. 28, 2026
Parton also knew how to tailor her jokes to any moment.
From Salon ● Aug. 28, 2026
The one whose eyes light up when he sees me, even though he doesn’t know and would hate it if he knew that his eyes gave him away.
From "Red Flags and Butterflies" by Sheryl Azzam
In a phenomenon known as “curve flattening,” the gain on the 30-year bond yield was more modest, causing a convergence.
From The Wall Street Journal ● Aug. 28, 2026
An 1859 geomagnetic storm known as the Carrington Event is often considered to be the benchmark for a worst-case scenario here on Earth.
From BBC ● Aug. 28, 2026
Since 1982, policymakers and prominent economists have gathered in this valley ringed by mountains in Grand Teton National Park -- known to most people more for its bison than for spirited debates on macroeconomics.
From Barron's ● Aug. 28, 2026
“He’s just such a cool horse,” Koch said, noting the gelding is known around the barn as “Clifford the Big Red Dog” because of his chestnut coat and a temperament Fenton describes as “sweet.”
From Los Angeles Times ● Aug. 28, 2026
The commanding officer was there, too, and Luc, which reassured me—of course I should have known that the commanding officer wouldn’t issue me any instructions without Luc’s knowing.
From "The Brightwood Code" by Monica Hesse
Sehida Abdurahmanovic, a member of the main association of mothers in Srebrenica, said knowing he died suffering was some solace to victims' families, but his conviction was more enduring.
From Barron's ● Aug. 28, 2026
I can’t count myself in their company, knowing that the collateral damage would likely be massive.
From Salon ● Aug. 28, 2026
We take comfort in knowing that Shelley’s work and the memories she created with those who loved her will continue to live on.”
From Los Angeles Times ● Aug. 28, 2026
Elaine said: "Me and all the family have got to live with that, knowing that he probably needn't have died. He was a fit, well man on the outside."
From BBC ● Aug. 28, 2026
I tried to sound casual, but apparently I’d never actually sounded casual in my life, because Grandma’s face broke into a knowing smile.
From "Bye Forever, I Guess" by Jodi Meadows
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.
