St. Ada, a Roman Catholic saint, was a 7th century nun, abbess, and dedicated virgin. She was the niece of Saint Engelbert, who was murdered by his own cousin; she and her family were very pious. She was a nun at Soissons, France, and subsequently an abbess at Saint-Julien de Prés Abbey, Le Mans, France. She is a patroness of religious women and nuns in France. St. Ada's feast day is December 4.