Synonyms: unknown, unknown quantity
Definition: a variable whose values are solutions of an equation
Similar words: variable
Definition: a symbol (like x or y) that is used in mathematical or logical expressions to represent a variable quantity
Synonyms: unknown quantity
Definition: a factor in a given situation whose bearing and importance is not apparent
Usage: I don't know what the new man will do; he's still an unknown quantity
Similar words: factor
Definition: anything that contributes causally to a result
Usage: a number of factors determined the outcome