Definition of isabella
                                                                                                    
                                                                            (noun) 
                                                                                                                                                         the 
queen of Castile whose 
marriage to Ferdinand of Aragon in 1469 
marked the 
beginning of the 
modern state of Spain; they instituted the Spanish Inquisition in 1478 and sponsored the voyages of Christopher Columbus in 1492 (1451-1504)