From Longman Dictionary of Contemporary Englishbotanical gardenboˌtanical ˈgarden noun [countable] HBPDLOa large public garden where many different types of flowers and plants are grown for scientific study
Examples from the Corpus
botanical garden• Trees from every continent turn King's Park into a giant botanical garden.• Another neat toy: an on-line tour of botanical garden Web sites.• Founded in 1673, this small walled garden is the oldest botanical garden in the country after Oxford's. 