"pilgrim's shell" meaning in English

{
  "forms": [
    {
      "form": "pilgrim's shells",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "pilgrims' shells",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "s",
        "2": "pilgrims' shells"
      },
      "expansion": "pilgrim's shell (plural pilgrim's shells or pilgrims' shells)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "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"
        },
        {
          "kind": "lifeform",
          "langcode": "en",
          "name": "Venerida order mollusks",
          "orig": "en:Venerida order mollusks",
          "parents": [
            "Bivalves",
            "Mollusks",
            "Animals",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A cockleshell used as a sign that one had visited the Holy Land."
      ],
      "id": "en-pilgrim's_shell-en-noun-X5ERvtfP",
      "links": [
        [
          "cockleshell",
          "cockleshell"
        ],
        [
          "Holy Land",
          "Holy Land"
        ]
      ],
      "raw_glosses": [
        "(historical) A cockleshell used as a sign that one had visited the Holy Land."
      ],
      "tags": [
        "historical"
      ]
    }
  ],
  "word": "pilgrim's shell"
}

{
  "forms": [
    {
      "form": "pilgrim's shells",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "pilgrims' shells",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "s",
        "2": "pilgrims' shells"
      },
      "expansion": "pilgrim's shell (plural pilgrim's shells or pilgrims' shells)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with historical senses",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Venerida order mollusks"
      ],
      "glosses": [
        "A cockleshell used as a sign that one had visited the Holy Land."
      ],
      "links": [
        [
          "cockleshell",
          "cockleshell"
        ],
        [
          "Holy Land",
          "Holy Land"
        ]
      ],
      "raw_glosses": [
        "(historical) A cockleshell used as a sign that one had visited the Holy Land."
      ],
      "tags": [
        "historical"
      ]
    }
  ],
  "word": "pilgrim's shell"
}