From Longman Dictionary of Contemporary Englishmorning dressˈmorning dress noun [uncountable] especially British EnglishDCC men’s formal clothes that include a morning coat, trousers, and a top hat, worn at daytime ceremonies such as weddings
Examples from the Corpus
morning dress• John had been best man; he looked so beautiful in morning dress, far more handsome than the groom.• Gentlemen will wear morning dress with top hat, or service dress. 