Dictionary.com
Thesaurus.com
Synonyms

unknown

American  
[uhn-nohn] / ʌnˈnoʊn /

adjective

  1. not known; not within the range of one's knowledge, experience, or understanding; strange; unfamiliar.

  2. not discovered, explored, identified, or ascertained.

    the unknown parts of Antarctica.

  3. not widely known; not famous; obscure.

    an unknown writer.


noun

  1. a thing, influence, area, factor, or person that is unknown.

    the many unknowns in modern medicine; The director cast an unknown in the leading role.

  2. Mathematics. a symbol representing an unknown quantity: in algebra, analysis, etc., frequently represented by a letter from the last part of the alphabet, as x, y, or z.

unknown British  
/ ʌnˈnəʊn /

adjective

  1. not known, understood, or recognized

  2. not established, identified, or discovered

    an unknown island

  3. not famous; undistinguished

    some unknown artist

  4. a person or thing whose action, effect, etc, is unknown or unpredictable

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

noun

  1. an unknown person, quantity, or thing

  2. maths a variable, or the quantity it represents, the value of which is to be discovered by solving an equation; a variable in a conditional equation

    3y = 4x + 5 is an equation in two unknowns

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • unknownness noun

Etymology

Origin of unknown

First recorded in 1250–1300, unknown is from the Middle English word unknow(e)n. See un- 1, known

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.

Producers had not previously confirmed how long the secret traitor would remain unknown.

From BBC

However, how the thalamus and cortex interact during circuit formation in the human brain has remained largely unknown.

From Science Daily

However, the coalition said the plane left three hours late without Zubaidi, who "fled to an unknown location".

From BBC

An international research team has discovered two previously unknown viruses in short-finned pilot whales and orcas from the Caribbean region of the North Atlantic Ocean.

From Science Daily

“This schedule is the result of a secretive process done by unknown people, without the benefit of public input,” Benjamin said in a statement.

From Salon