Main entry: unknown, unknown quantity
Definition: a variable whose values are solutions of an equation
Main entry: terra incognita, unknown, unknown region
Definition: an unknown and unexplored region
Usage: they came like angels out the unknown
Main entry: stranger, unknown, alien
Definition: anyone who does not belong in the environment in which they are found
Main entry: unidentified, unknown, unnamed, nameless
Definition: being or having an unknown or unnamed source
Usage: a poem by an unknown author; corporations responsible to nameless owners; an unnamed donor
Definition: not known before
Usage: used many strange words; saw many strange faces in the crowd; don't let anyone unknown into the house
Main entry: unsung, unknown, obscure
Definition: not famous or acclaimed
Usage: an obscure family; unsung heroes of the war
Main entry: unknown
Definition: not known
Usage: an unknown amount; an unknown island; an unknown writer; an unknown source
Main entry: unknown
Definition: not known to exist
Usage: things obscurely felt surged up from unknown depths