"falling block" meaning in English

{
  "forms": [
    {
      "form": "falling blocks",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "falling block (plural falling blocks)",
      "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": "English entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Firearms",
          "orig": "en:Firearms",
          "parents": [
            "Weapons",
            "Hunting",
            "Military",
            "Tools",
            "Human activity",
            "Society",
            "Technology",
            "Human behaviour",
            "All topics",
            "Human",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Weapons",
          "orig": "en:Weapons",
          "parents": [
            "Hunting",
            "Military",
            "Tools",
            "Human activity",
            "Society",
            "Technology",
            "Human behaviour",
            "All topics",
            "Human",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A single-shot firearm action in which a solid metal breechblock slides vertically in grooves cut into the breech of the rifle and actuated by a lever."
      ],
      "id": "en-falling_block-en-noun-iiUdgUI5",
      "links": [
        [
          "action",
          "action"
        ],
        [
          "breechblock",
          "breechblock"
        ]
      ],
      "wikipedia": [
        "falling block"
      ]
    }
  ],
  "word": "falling block"
}

{
  "forms": [
    {
      "form": "falling blocks",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "falling block (plural falling blocks)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English entries with topic categories using raw markup",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys",
        "en:Firearms",
        "en:Weapons"
      ],
      "glosses": [
        "A single-shot firearm action in which a solid metal breechblock slides vertically in grooves cut into the breech of the rifle and actuated by a lever."
      ],
      "links": [
        [
          "action",
          "action"
        ],
        [
          "breechblock",
          "breechblock"
        ]
      ],
      "wikipedia": [
        "falling block"
      ]
    }
  ],
  "word": "falling block"
}