"knocking mill" meaning in English

{
  "forms": [
    {
      "form": "knocking mills",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "knocking mill (plural knocking mills)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "bold_text_offsets": [
            [
              138,
              151
            ]
          ],
          "ref": "1828, Thomas Keightley, The Fairy Mythology, volume II, London: William Harrison Ainsworth, page 167:",
          "text": "Up he started - the wind arose - the corn was chopped - the outlyers were foddered - the hand-mill moved around, as by instinct - and the knocking-mill did its work with amazing rapidity.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A type of mill powered by running water that repeatedly applies a heavy hammer to grain, ore, etc."
      ],
      "id": "en-knocking_mill-en-noun-zzJSIKYK",
      "links": [
        [
          "water",
          "water"
        ],
        [
          "hammer",
          "hammer"
        ],
        [
          "grain",
          "grain"
        ],
        [
          "ore",
          "ore"
        ]
      ]
    }
  ],
  "word": "knocking mill"
}

{
  "forms": [
    {
      "form": "knocking mills",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "knocking mill (plural knocking mills)",
      "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 quotations",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "bold_text_offsets": [
            [
              138,
              151
            ]
          ],
          "ref": "1828, Thomas Keightley, The Fairy Mythology, volume II, London: William Harrison Ainsworth, page 167:",
          "text": "Up he started - the wind arose - the corn was chopped - the outlyers were foddered - the hand-mill moved around, as by instinct - and the knocking-mill did its work with amazing rapidity.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A type of mill powered by running water that repeatedly applies a heavy hammer to grain, ore, etc."
      ],
      "links": [
        [
          "water",
          "water"
        ],
        [
          "hammer",
          "hammer"
        ],
        [
          "grain",
          "grain"
        ],
        [
          "ore",
          "ore"
        ]
      ]
    }
  ],
  "word": "knocking mill"
}