Double; consisting of two similar and corresponding parts.
                                                            
                                                     
                        
                                                
                        
                        
                            A compound crystal composed of two or more crystals, or parts of crystals, in reversed position with reference to each other.
                                                            
                                                     
                        
                                                
                        
                        
                            To separate into two parts; to part; to divide; hence, to remove; also, to strip; to rob.
                                                            
                                                     
                        
                                                
                                                     
                        
                        
                            A rational intergrowth of two or more single crystals of the same mineral in a mathematically describable manner. The symmetry of the two parts may be reflected about a common plane, axis or center.
                                                            
                                                     
                        
                                                
                        
                        
                            A hotel room containing two single beds.
                                                            
                                                     
                        
                                                
                        
                        
                            Two or more crystals that intergrow in a specific method. May also be used in verb form, as "Two crystals may twin to form a cross."
                                                            
                                                     
                        
                                                
                        
                        
                            grow as twins; "twin crystals" 
                                                            
                                                     
                        
                                                
                        
                        
                        
                                                
                        
                        
                            a number that has proved to appear in either two squares and helps disprove its presence in another part of the grid
                                                            
                                                     
                        
                                                
                        
                        
                            a room with two single beds
                                                            
                                                     
                        
                                                
                        
                        
                        
                                                
                        
                        
                            a single crystal composed of two or more parts with any part in reversed structural orientation to the next, or interpenetrated
                                                            
                                                     
                        
                                                
                        
                        
                            A bed that measures 38" by 74".
                                                            
                                                     
                        
                                                
                        
                        
                            Crystals intergrown in a fixed relationship, with unvarying angles.
                                                            
                                                     
                        
                                                
                        
                        
                            A bed that measures 39 inches wide by 75 inches long.
                                                            
                                                     
                        
                                                
                        
                        
                            Term referring to two SQers who share a brain. (see " SQer".) i.e. Zsenya and Moey or Jane and Alphie.