From Longman Dictionary of Contemporary Englishgarden partyˈgarden ˌparty noun [countable] British EnglishDLO a formal party for a lot of people which is held in a large garden in the afternoon
Examples from the Corpus
garden party• I met her at a garden party in San Francisco the summer I got hepatitis.• Joe even managed an invitation to a garden party given for the generalissimo and Madame Chiang.• I emphasize that I have no wish to come across here as the skunk at the process improvement garden party.• I was at his recent garden party and I have actually shaken his hand.• One could imagine her at a shires garden party or a race meeting.• The garden party held in July, took place at the Palace of Holyrood House. 