( AmE post office ) n [ U ]
a traditional children’s game, played e.g. at parties, in which one player pretends to be a postman delivering a letter, knocks on a door, and kisses the player who opens it.
POSTMAN’S KNOCK
Meaning of POSTMAN’S KNOCK in English
Oxford guide to British and American culture English vocabulary. Руководство по британской и американской культуре, Оксфордский английский словарь. 2005