unknown

B2 · Upper Intermediate Uncountable noun

n. a place, situation, or fact that nobody knows anything about yet.

n. an unexplored or unidentified place, situation, or realm of knowledge; often used with the definite article 'the'.

“Space travel is a journey into the unknown for most of us.”

“The explorers faced the great unknown with a mixture of trepidation and scientific curiosity, unsure of what the deep-sea trenches might reveal.”

C1 · Advanced Countable noun Formal

n. a person who is not famous or whose identity is not known.

n. an individual who lacks fame, social standing, or a public identity.

“He was a complete unknown before he won the national talent show.”

“The candidate was a political unknown until a series of viral debates propelled her to the forefront of the national conversation.”

B2 · Upper Intermediate Countable noun Mathematics Technical

n. a symbol, like x or y, that represents a number you need to find.

n. a quantity or variable in a mathematical equation whose value is initially unspecified and must be determined.

“In the equation 2x + 5 = 11, x is the unknown.”

“The physicist introduced a second unknown into the formula to account for the unexpected variance in gravitational pull during the experiment.”