unknown

[ uhn-nohn ]
/ ʌnˈnoʊn /

adjective

not known; not within the range of one's knowledge, experience, or understanding; strange; unfamiliar.
not discovered, explored, identified, or ascertained: the unknown parts of Antarctica.
not widely known; not famous; obscure: an unknown writer.

noun

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.
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.

Origin of unknown

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

Example sentences from the Web for unknown

British Dictionary definitions for unknown

unknown
/ (ʌnˈnəʊn) /

adjective

not known, understood, or recognized
not established, identified, or discovered an unknown island
not famous; undistinguished some unknown artist
unknown quantity a person or thing whose action, effect, etc, is unknown or unpredictable

noun

an unknown person, quantity, or thing
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

Derived forms of unknown

unknownness, noun