"kettle bottom" meaning in English

{
  "forms": [
    {
      "form": "kettle bottoms",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "kettle bottom (plural kettle bottoms)",
      "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": "topical",
          "langcode": "en",
          "name": "Mining",
          "orig": "en:Mining",
          "parents": [
            "Industries",
            "Business",
            "Economics",
            "Society",
            "Social sciences",
            "All topics",
            "Sciences",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A smooth cylindrical piece of petrified wood in the ceiling of a mine which may drop down and injure or kill miners"
      ],
      "id": "en-kettle_bottom-en-noun-MjX9QIg6",
      "links": [
        [
          "mining",
          "mining#Noun"
        ],
        [
          "petrified",
          "petrified"
        ],
        [
          "wood",
          "wood"
        ],
        [
          "mine",
          "mine"
        ]
      ],
      "raw_glosses": [
        "(mining) A smooth cylindrical piece of petrified wood in the ceiling of a mine which may drop down and injure or kill miners"
      ],
      "topics": [
        "business",
        "mining"
      ]
    }
  ],
  "word": "kettle bottom"
}

{
  "forms": [
    {
      "form": "kettle bottoms",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "kettle bottom (plural kettle bottoms)",
      "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",
        "en:Mining"
      ],
      "glosses": [
        "A smooth cylindrical piece of petrified wood in the ceiling of a mine which may drop down and injure or kill miners"
      ],
      "links": [
        [
          "mining",
          "mining#Noun"
        ],
        [
          "petrified",
          "petrified"
        ],
        [
          "wood",
          "wood"
        ],
        [
          "mine",
          "mine"
        ]
      ],
      "raw_glosses": [
        "(mining) A smooth cylindrical piece of petrified wood in the ceiling of a mine which may drop down and injure or kill miners"
      ],
      "topics": [
        "business",
        "mining"
      ]
    }
  ],
  "word": "kettle bottom"
}