: not known or not well-known
also
: having an unknown value
an unknown quantity
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
Synonyms
Examples of unknown in a Sentence
Adjective
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
Noun
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 on the Web
Greta Cross, USA TODAY, 26 Oct. 2024
Fifty-five percent of an organization’s data is dark—untapped and unknown.
—Sean Nathaniel, Forbes, 25 Oct. 2024
Carly Tagen-Dye, People.com, 11 Oct. 2024
The question of how to measure the rise and fall of biodiversity numbers in the past has therefore been plagued by unknowns.
—Asher Elbein, Scientific American, 24 Sep. 2024
See all Example Sentences for unknown 
Adjective
Per the policy that established the Montgomery County Citizens Review Committee, committee meetings are to be held privately, so the committee's decision-making process is unknown.
—Greta Cross, USA TODAY, 26 Oct. 2024
Fifty-five percent of an organization’s data is dark—untapped and unknown.
—Sean Nathaniel, Forbes, 25 Oct. 2024
Noun
The novelist and poet appeared on NPR's 'Wild Card with Rachel Martin' podcast on Oct. 3
Comments
Margaret Atwood does not fear the great unknown.
—Carly Tagen-Dye, People.com, 11 Oct. 2024
The question of how to measure the rise and fall of biodiversity numbers in the past has therefore been plagued by unknowns.
—Asher Elbein, Scientific American, 24 Sep. 2024
See all Example Sentences for unknown
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'unknown.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Articles Related to unknown
Dictionary Entries Near unknown
Cite this Entry
“Unknown.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unknown. Accessed 30 Oct. 2024.
Copy CitationKids Definition
unknown
1 of 2 adjective
un·known
ˌən-ˈnōn 
: not known
also
: having an unknown value
an unknown quantity
unknown
2 of 2 noun1
: something that is unknown
2
: a symbol (as x, y, or z) representing a quantity whose value is unknown
an equation with two unknowns
Love words? Need even more definitions?
Merriam-Webster unabridged
Share