From Longman Dictionary of Contemporary Englishcocktail loungeˈcocktail ˌlounge noun [countable] DFDTBBa public room in a hotel, restaurant etc, where you can buy alcoholic drinks
Examples from the Corpus
cocktail lounge• The gallery looks so much like a cocktail lounge you may be tempted to ask a guard for a martini.• At the restaurant they were ushered into a small, extremely hot cocktail lounge. 