unknown

1 of 2

adjective

un·​known ˌən-ˈnōn 

: not known or not well-known

also : having an unknown value

an unknown quantity

unknown

2 of 2

noun

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

Adjective

• unbeknownst
• unbeknown

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

Adjective

To begin with, having only 107 days to run a presidential campaign would be a tall order for any politician, let alone a relatively unknown Black woman from what is arguably the most liberal state in the country. —Letters To The Editor, The Mercury News, 15 Nov. 2024

The lack of regulation may help explain why the state has the nation’s lowest autopsy rate in child deaths attributed to unnatural or unknown causes — a category that includes suicides, homicides, crashes, drownings, overdoses and sudden infant deaths. —Audrey Dutton, ProPublica, 11 Nov. 2024

Noun

This campaign has all the hallmarks of a lost season, leading to a great unknown in future years. —Dieter Kurtenbach, The Mercury News, 18 Nov. 2024

Life beyond Earth is among the greatest unknowns in science. —Joel Achenbach, arkansasonline.com, 20 Oct. 2024

Word History

First Known Use

Adjective

14th century, in the meaning defined above

Noun

1597, in the meaning defined at sense 1

Phrases Containing unknown

• big unknown
• fear of the unknown
• of unknown origin
• the unknown
• unknown quantity
• unknown to

Kids Definition

unknown

1 of 2 adjective

un·​known ˌən-ˈnōn 

: not known

also : having an unknown value

an unknown quantity

unknown

2 of 2 noun

1

: something that is unknown

2

: a symbol (as x, y, or z) representing a quantity whose value is unknown

an equation with two unknowns