"cellar flap" meaning in English

{
  "etymology_text": "So called because it might be danced on the cellar flap of a public house by somebody with no money, who could not enter.",
  "forms": [
    {
      "form": "cellar flaps",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "cellar flap (plural cellar flaps)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "British English",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Synonym of double shuffle"
      ],
      "id": "en-cellar_flap-en-noun-f8YQUJly",
      "links": [
        [
          "double shuffle",
          "double shuffle#English"
        ]
      ],
      "raw_glosses": [
        "(UK, slang, obsolete) Synonym of double shuffle"
      ],
      "synonyms": [
        {
          "tags": [
            "synonym",
            "synonym-of"
          ],
          "word": "double shuffle"
        }
      ],
      "tags": [
        "UK",
        "obsolete",
        "slang"
      ]
    }
  ],
  "word": "cellar flap"
}

{
  "etymology_text": "So called because it might be danced on the cellar flap of a public house by somebody with no money, who could not enter.",
  "forms": [
    {
      "form": "cellar flaps",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "cellar flap (plural cellar flaps)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "British English",
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English slang",
        "English terms with obsolete senses",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "Synonym of double shuffle"
      ],
      "links": [
        [
          "double shuffle",
          "double shuffle#English"
        ]
      ],
      "raw_glosses": [
        "(UK, slang, obsolete) Synonym of double shuffle"
      ],
      "synonyms": [
        {
          "tags": [
            "synonym",
            "synonym-of"
          ],
          "word": "double shuffle"
        }
      ],
      "tags": [
        "UK",
        "obsolete",
        "slang"
      ]
    }
  ],
  "word": "cellar flap"
}