"jackstone" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "jack",
        "3": "stone"
      },
      "expansion": "jack + stone",
      "name": "compound"
    }
  ],
  "etymology_text": "From jack + stone.",
  "forms": [
    {
      "form": "jackstones",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "jackstone (plural jackstones)",
      "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"
        }
      ],
      "derived": [
        {
          "word": "jackstone calculus"
        }
      ],
      "glosses": [
        "A jack; one of the playing pieces in the game of jacks."
      ],
      "id": "en-jackstone-en-noun-j1yVxUMt",
      "links": [
        [
          "jack",
          "jack"
        ],
        [
          "jacks",
          "jacks"
        ]
      ]
    }
  ],
  "word": "jackstone"
}

{
  "derived": [
    {
      "word": "jackstone calculus"
    }
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "jack",
        "3": "stone"
      },
      "expansion": "jack + stone",
      "name": "compound"
    }
  ],
  "etymology_text": "From jack + stone.",
  "forms": [
    {
      "form": "jackstones",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "jackstone (plural jackstones)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English compound terms",
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "A jack; one of the playing pieces in the game of jacks."
      ],
      "links": [
        [
          "jack",
          "jack"
        ],
        [
          "jacks",
          "jacks"
        ]
      ]
    }
  ],
  "word": "jackstone"
}