postman's knock

/P OW1 S T M AH0 N EH0 S N AA0 K/
noun
  1. 1

    A place (building, office, shop, or counter) concerned with the business of delivering letters, post or mail and selling stamps, etc.

  2. 2

    An organisation that delivers letters.

  3. 3

    A party game involving the exchange of kisses.

Source: https://en.wiktionary.org/wiki/post%20office, https://en.wiktionary.org/wiki/postman's%20knock