Rosario \r(o)-sa-rio\ as a boy's name (also used as girl's name Rosario), is pronounced roe-ZAR-ee-oh. It is of Latin origin, and the meaning of Rosario is "rosary". From Rosarius. In Roman Catholic countries, this name has traditionally been given to those born on the first Sunday in October, the Feast of "Our Lady of the Rosary". This name is feminine in Spanish and masculine in Italian.