From Longman Dictionary of Contemporary Englishmasked ballˌmasked ˈball noun [countable] DLa formal dance at which everyone wears masks
Examples from the Corpus
masked ball• You can make different kinds of mask for a witch or a pirate, or more elaborate ones for a masked ball.• The city seems like it is preparing for a masked ball.• Mercutio is in high spirits, teasing Romeo about his love as they prepare to go to the Capulet masked ball.• For several decades, El Carnaval remained an elitist event that ended with an elegant masked ball.• Ideas had been ruthlessly stolen from the Nice masked ball at Mardi Gras.• He had just won her gracious consent to attend the Grand Duke Igor's masked ball in two weeks' time. 