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