"postman's knock" meaning in English

{
  "head_templates": [
    {
      "args": {
        "1": "?"
      },
      "expansion": "postman's knock",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "_dis": "86 14",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "Synonym of post office (“party game involving the exchange of kisses”)"
      ],
      "id": "en-postman's_knock-en-noun-SsJXXA9e",
      "links": [
        [
          "post office",
          "post office#English"
        ]
      ],
      "raw_glosses": [
        "(uncountable) Synonym of post office (“party game involving the exchange of kisses”)"
      ],
      "synonyms": [
        {
          "extra": "party game involving the exchange of kisses",
          "tags": [
            "synonym",
            "synonym-of"
          ],
          "word": "post office"
        }
      ],
      "tags": [
        "uncountable"
      ]
    },
    {
      "categories": [],
      "glosses": [
        "A double knock at the door to indicate the delivery of letters or telegrams."
      ],
      "id": "en-postman's_knock-en-noun-SNCtDNVZ",
      "raw_glosses": [
        "(countable) A double knock at the door to indicate the delivery of letters or telegrams."
      ],
      "tags": [
        "countable"
      ]
    }
  ],
  "word": "postman's knock"
}

{
  "categories": [
    "English countable nouns",
    "English entries with incorrect language header",
    "English lemmas",
    "English multiword terms",
    "English nouns",
    "English nouns with unknown or uncertain plurals"
  ],
  "head_templates": [
    {
      "args": {
        "1": "?"
      },
      "expansion": "postman's knock",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English uncountable nouns"
      ],
      "glosses": [
        "Synonym of post office (“party game involving the exchange of kisses”)"
      ],
      "links": [
        [
          "post office",
          "post office#English"
        ]
      ],
      "raw_glosses": [
        "(uncountable) Synonym of post office (“party game involving the exchange of kisses”)"
      ],
      "synonyms": [
        {
          "extra": "party game involving the exchange of kisses",
          "tags": [
            "synonym",
            "synonym-of"
          ],
          "word": "post office"
        }
      ],
      "tags": [
        "uncountable"
      ]
    },
    {
      "categories": [
        "English countable nouns"
      ],
      "glosses": [
        "A double knock at the door to indicate the delivery of letters or telegrams."
      ],
      "raw_glosses": [
        "(countable) A double knock at the door to indicate the delivery of letters or telegrams."
      ],
      "tags": [
        "countable"
      ]
    }
  ],
  "word": "postman's knock"
}