From Longman Dictionary of Contemporary EnglishBuck's FizzBuck’s Fizz /ˌbʌks ˈfɪz/ noun [countable, uncountable] British English DFDa mixture of champagne and orange juice, or a glass of this
Examples from the Corpus
Buck's Fizz• Zimmermann Graeff's Exotic Buck's Fizz is made with delicious tropical fruit juices including pineapple and passion fruit.• I find Buck's Fizz depressing ... or any music that expresses no humanity.• Sainsbury's Buck's Fizz is a light and very attractive sparkling blend of wine and orange juice. 