"fireclay" meaning in English

{
  "forms": [
    {
      "form": "fireclays",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "fireclay (countable and uncountable, plural fireclays)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "fire clay"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1961 February, D. Bertram, “The lines to Wetherby and their traffic”, in Trains Illustrated, page 101",
          "text": "On the descent the line is often in cuttings; some are high, such as at Scarcroft, where a cut through firestone and fireclay was necessary, and near Bardsey, where the line threads a deep tree-lined gorge.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Alternative spelling of fire clay"
      ],
      "id": "en-fireclay-en-noun-JSmV7vS4",
      "links": [
        [
          "fire clay",
          "fire clay#English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative",
        "countable",
        "uncountable"
      ]
    }
  ],
  "word": "fireclay"
}

{
  "forms": [
    {
      "form": "fireclays",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "fireclay (countable and uncountable, plural fireclays)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "fire clay"
        }
      ],
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English terms with quotations",
        "English uncountable nouns"
      ],
      "examples": [
        {
          "ref": "1961 February, D. Bertram, “The lines to Wetherby and their traffic”, in Trains Illustrated, page 101",
          "text": "On the descent the line is often in cuttings; some are high, such as at Scarcroft, where a cut through firestone and fireclay was necessary, and near Bardsey, where the line threads a deep tree-lined gorge.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Alternative spelling of fire clay"
      ],
      "links": [
        [
          "fire clay",
          "fire clay#English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative",
        "countable",
        "uncountable"
      ]
    }
  ],
  "word": "fireclay"
}