best man
Longman Dictionary of Contemporary English 5++LDOCE 5++ˌbest ˈman noun [singular] MARRYthe man who helps the bridegroom at a wedding ceremony 男傧相,伴郎
Examples from the Corpus
best man• And her frail brother bravely struggled from his sick bed to be best man.• They were close friends, and Critchley was the best man at Heseltine's wedding.• The bride walked to the church with the best man with the groom following.ˌbest ˈman nounChineseSyllable
helps man bridegroom the wedding a the Corpus at who ceremony

