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:
He also said he did not know whether the complaints were escalated to management level within the health board.
From BBC ● Aug. 16, 2026
The couple met briefly while playing at various beach volleyball events, but they really got to know each other and clicked while spending three weeks together during tournaments in China, India and the Philippines.
From Los Angeles Times ● Aug. 16, 2026
As a military son and a military husband, I know how deeply military families feel about every milestone missed and every week added to a combat deployment.
From The Wall Street Journal ● Aug. 16, 2026
Whether Washington would have approved of Trump’s ballroom is impossible to know.
From Salon ● Aug. 16, 2026
I know my destiny is to play awe-inspiring music in breathtaking venues.
From "Split the Sky" by Marie Arnold
Who knows if the English game will be marching on together as hoped by those that have staked so much on this direction?
From BBC ● Aug. 16, 2026
“There’s a lot of stuff, without getting to granular with it. ... He knows himself in terms of, ‘Am I able to stack back-to- back days?
From Los Angeles Times ● Aug. 16, 2026
"But no one knows for sure what will happen or not. You just rely on your intuition and survival instinct," the 34-year-old said.
From Barron's ● Aug. 16, 2026
He knows he cannot count on the support of his father, or his brothers, indefinitely.
From The Wall Street Journal ● Aug. 15, 2026
I was a Hello Girl and now I am here, a hermit in a boardinghouse, protected by a disheveled fortress of my dirty clothes and empty tins, and Theo knows absolutely nothing.
From "The Brightwood Code" by Monica Hesse
It bounced off the plate, ending his outing and, for all anyone knew, his pitching career.
From Los Angeles Times ● Aug. 16, 2026
Bank of China Tower, Hong Kong, 2006: I was meeting with an investor I knew on the 65th floor of a reflective glass building.
From The Wall Street Journal ● Aug. 16, 2026
A former engineer at the company, Béjar has claimed for years that Meta’s child-safety tools were ineffective and that top executives knew its products were harming children.
From Los Angeles Times ● Aug. 16, 2026
Lauren went on to explain the phases of the menstrual cycle was not something she knew about until after having children.
From BBC ● Aug. 16, 2026
Not in any of the languages she knew.
From "Legendary Frybread Drive-In" by Cynthia Leitich Smith
In evidence presented to the inquiry, he said he had submitted three separate formal situation, background, assessment and recommendations, known as SBARs, relating to the QEUH.
From BBC ● Aug. 16, 2026
The spread between the cost of producing a barrel of gasoline and the cost of the crude oil needed to produce it — known among traders as the “crack spread” — has widened sharply.
From MarketWatch ● Aug. 16, 2026
The gradual breakdown of cartilage is known as osteoarthritis, a condition which affects more than 500 million people worldwide.
From Science Daily ● Aug. 16, 2026
Also known as “breakbone fever” — the painful, debilitating disease, which can be fatal, is caused by a virus adapted to an invasive, African mosquito known as Aedes aegypti.
From Los Angeles Times ● Aug. 16, 2026
This came to be known as the Red Scare.
From "At Last She Stood" by Erin Entrada Kelly
“Any use of Mr. Daniels’ NIL occurring after LSU’s receipt of this notice will be deemed knowing and willful and will be pursued vigorously through all available legal and equitable remedies.”
From Los Angeles Times ● Aug. 13, 2026
“At the end of the day, we know that those who are serving have to have comfort knowing that they’re getting properly taken care of,” he said in an interview with CNN on Thursday.
From The Wall Street Journal ● Aug. 13, 2026
The student, who is also a freelance translator, has also found it hard to concentrate on lectures knowing he could be missing out on work opportunities.
From Barron's ● Aug. 13, 2026
"I can't thank the owners of MSG for allowing us to get the opportunity to do that, knowing that we wanted a private event and everything, and it was perfect," he added.
From BBC ● Aug. 12, 2026
But I couldn’t imagine knowing how to finish my sentence.
From "The Brightwood Code" by Monica Hesse
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.
