unknown

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adjective un·known \ ˌən-ˈnōn \

Definition of unknown

:not known or not well-known; also :having an unknown value

an unknown quantity

See unknown defined for English-language learners

See unknown defined for kids

Examples of unknown in a Sentence

a disease of unknown cause
Much remains unknown about his early life.
Her music was previously unknown outside of Asia.
An unknown number of cases go unreported.
The victim's attacker was unknown to her.
For some unknown reason, my computer crashed.
a book of unknown poems

Recent Examples of unknown from the Web

Of those, B strains were found to cause 34 cases, but the strain was unknown in 40 cases.

— michele munz, The Seattle Times, "College students: There’s a new vaccine you should consider," 30 Aug. 2017
A computer scientist at the University of Manchester has found a previously unknown cache of 148 letters written by Alan Turing, the famed mathematician, codebreaker and godfather of the computer age, reports Josh Halliday at The Guardian.

— jason daley, Smithsonian, "New Letters Show Alan Turing Wasn’t a Fan of the U.S.A.," 30 Aug. 2017
The condition of the victim is unknown at this time, according to police spokesman Vadim Dale.

— thomas novelly, The Courier-Journal, "Person found shot at Norton Healthcare Pavillion on Broadway," 28 Aug. 2017
The National Weather Service was very blunt about what is unfolding in Texas: This event is unprecedented & all impacts are unknown & beyond anything experienced.

— leigh morgan, AL.com, "Tropical Storm Harvey causing widespread, catastrophic flooding in Texas and it could get worse," 27 Aug. 2017
The video shows Mattis in what appears to be an impromptu visit to troops at an unknown location –

— benjamin hart, Daily Intelligencer, "Mattis Tells Troops to ‘Hold the Line’ Amid Divisions in U.S.," 26 Aug. 2017
Plus, the popularity of shows like The Big Bang Theory and Game of Thrones have earned some formerly unknown actors major raises.

— courtney campbell, Country Living, "Here's How Much Your Favorite Television Actors and Hosts Really Make," 25 Aug. 2017
Even after researchers corrected for the recent growth in U.S. waistlines and life spans, the increase still held, meaning—say scientists—that other, still unknown, factors are causing more people to suffer from aching knees.

— ryan cross, Science | AAAS, "Top stories: Disappearing Zika, tricky eclipses, and the world’s oldest ice cores," 18 Aug. 2017
Thousands of white nationalists and right-wing groups descended on the town and violently clashed with counter-protests, leading to an unknown number of arrests.

— paula rogo, Essence.com, "Trump Remains Silent After Hate-Filled Racist Clashes In Charlottesville," 12 Aug. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'unknown.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of unknown

14th century

unknown Synonyms

Synonyms

unbeknownst (also unbeknown)

Antonyms

familiar, hackneyed, old, time-honored, tired, warmed-over

Related Words

unperceived, unrecognized, unsuspected; unaware, unconscious, unmindful; unknowing, unsuspecting, unwitting; ignorant, unacquainted, unfamiliar

Near Antonyms

conventional, established, traditional, tried, tried-and-true; derivative, imitative

unknown

noun

Definition of unknown

1 :one that is not known or not well-known; especially :a person who is little known (as to the public)

2 :something that requires discovery, identification, or clarification: such as

a :a symbol (such as x, y, or z) in a mathematical equation representing an unknown quantity

b :a specimen (as of bacteria or mixed chemicals) required to be identified as an exercise in appropriate laboratory techniques

See unknown defined for English-language learners

Examples of unknown in a Sentence

explorers venturing off into the unknown
A fear of the unknown kept her from changing jobs.
The director cast an unknown in the lead role.
We're facing too many unknowns.

Recent Examples of unknown from the Web

Of course, Dobrev’s most infamous leap into the unknown was her decision in 2015 to leave The Vampire Diaries, sending fans, costars, and network executives into a tailspin.

— Harper's BAZAAR, "Nina's Night Out," 17 Aug. 2017
However, the plan would impose an unknown — and likely unfunded — cost on local and state courts because officials would have to install lockers or other secure storage for which to temporarily house visitors’ firearms.

— kristen m. clark, miamiherald, "Got a court date and want to take your gun? Florida to consider it again.," 10 Aug. 2017
There are many unknowns in how the case is going now.

— hannah sparling, Cincinnati.com, "Drug charges, search warrants in Goshen teacher case," 19 July 2017
Kristofer Hivju (Tormund), Gwendoline Christie (Brienne), Pedro Pascal (Oberyn Martell), Bella Ramsey (Lyanna Mormont)—were mostly unknowns who carried no baggage of previous performances with them, and were able to blend seamlessly into the world.

— joanna robinson, HWD, "Game of Thrones: Are Famous Faces Really Ruining Westeros?," 19 July 2017
Creation of a New Weapons System The first point is that the introduction of new technology should not have any risks (or unknowns.)

— robert ellinger, sandiegouniontribune.com, "How to develop a disruptive system," 26 June 2017
Trump not only doesn’t know the unknowns but appears to have no interest in even knowing the knowns.

— graydon carter, The Hive, "Donald Trump: A Pillar of Ignorance and Certitude," 19 June 2017
USA TODAY Sports ERIN, Wis. — Brooks Koepka has never feared the unknown.

— steve dimeglio, The Courier-Journal, "Brooks Koepka's worldwide golf odyssey culminates in U.S. Open title," 18 June 2017
There must be something in the water in Miami that makes everyone so welcoming and so enthusiastic about the unknown.

— nancy dahlberg, miamiherald, "Facebook alum pulls curtain on TheVentureCity, launching in Miami," 12 June 2017

First Known Use of unknown

1597

UNKNOWN Defined for English Language Learners

unknown

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adjective

Definition of unknown for English Language Learners

: not known
: not well-known : not famous

unknown

noun

Definition of unknown for English Language Learners

the unknown : a place, situation, or thing that you do not know about or understand
: a person who is not famous or well-known
: something that is not known or not yet discovered

UNKNOWN Defined for Kids

unknown

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adjective un·known \ ˌən-ˈnōn \

Definition of unknown for Students

:not known

… it was cut all over with strange lines and figures that might be the letters of an unknown language.
—C. S. Lewis, The Lion, the Witch and the Wardrobe