"drop hammer" meaning in English

{
  "forms": [
    {
      "form": "drop hammers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "drop hammer (plural drop hammers)",
      "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": "Mechanical engineering",
          "orig": "en:Mechanical engineering",
          "parents": [
            "Engineering",
            "Applied sciences",
            "Technology",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1961 November, “Talking of Trains: The North Eastern's new rail-mounted piling unit”, in Trains Illustrated, page 646",
          "text": "On embankments these troughs are supported by piles driven into the ground and recent practice has been to drive them in by a drop hammer, manually operated from a railway wagon, [...].",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A heavy weight that is raised and then allowed to drop, as used for piledriving and drop-forging."
      ],
      "id": "en-drop_hammer-en-noun-Sw~tSXnD",
      "links": [
        [
          "mechanical engineering",
          "mechanical engineering"
        ],
        [
          "piledriving",
          "piledriving"
        ]
      ],
      "raw_glosses": [
        "(mechanical engineering) A heavy weight that is raised and then allowed to drop, as used for piledriving and drop-forging."
      ],
      "topics": [
        "engineering",
        "mechanical",
        "mechanical-engineering",
        "natural-sciences",
        "physical-sciences"
      ]
    }
  ],
  "word": "drop hammer"
}

{
  "forms": [
    {
      "form": "drop hammers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "drop hammer (plural drop hammers)",
      "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",
        "en:Mechanical engineering"
      ],
      "examples": [
        {
          "ref": "1961 November, “Talking of Trains: The North Eastern's new rail-mounted piling unit”, in Trains Illustrated, page 646",
          "text": "On embankments these troughs are supported by piles driven into the ground and recent practice has been to drive them in by a drop hammer, manually operated from a railway wagon, [...].",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A heavy weight that is raised and then allowed to drop, as used for piledriving and drop-forging."
      ],
      "links": [
        [
          "mechanical engineering",
          "mechanical engineering"
        ],
        [
          "piledriving",
          "piledriving"
        ]
      ],
      "raw_glosses": [
        "(mechanical engineering) A heavy weight that is raised and then allowed to drop, as used for piledriving and drop-forging."
      ],
      "topics": [
        "engineering",
        "mechanical",
        "mechanical-engineering",
        "natural-sciences",
        "physical-sciences"
      ]
    }
  ],
  "word": "drop hammer"
}