"neck down" meaning in English

{
  "forms": [
    {
      "form": "necks down",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "necking down",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "necked down",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "necked down",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "neck down (third-person singular simple present necks down, present participle necking down, simple past and past participle necked down)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "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 phrasal verbs formed with \"down\"",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "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"
        }
      ],
      "glosses": [
        "To alter (a cartridge) by forcing it into a smaller calibre and size."
      ],
      "id": "en-neck_down-en-verb-43~2VfWz",
      "links": [
        [
          "firearm",
          "firearm"
        ],
        [
          "alter",
          "alter"
        ],
        [
          "cartridge",
          "cartridge"
        ],
        [
          "calibre",
          "calibre"
        ]
      ],
      "raw_glosses": [
        "(firearms, transitive) To alter (a cartridge) by forcing it into a smaller calibre and size."
      ],
      "related": [
        {
          "word": "neck up"
        },
        {
          "word": "fireform"
        }
      ],
      "tags": [
        "transitive"
      ],
      "topics": [
        "engineering",
        "firearms",
        "government",
        "military",
        "natural-sciences",
        "physical-sciences",
        "politics",
        "tools",
        "war",
        "weaponry"
      ]
    }
  ],
  "word": "neck down"
}

{
  "forms": [
    {
      "form": "necks down",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "necking down",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "necked down",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "necked down",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "neck down (third-person singular simple present necks down, present participle necking down, simple past and past participle necked down)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "related": [
    {
      "word": "neck up"
    },
    {
      "word": "fireform"
    }
  ],
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English phrasal verbs",
        "English phrasal verbs formed with \"down\"",
        "English transitive verbs",
        "English verbs",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Firearms"
      ],
      "glosses": [
        "To alter (a cartridge) by forcing it into a smaller calibre and size."
      ],
      "links": [
        [
          "firearm",
          "firearm"
        ],
        [
          "alter",
          "alter"
        ],
        [
          "cartridge",
          "cartridge"
        ],
        [
          "calibre",
          "calibre"
        ]
      ],
      "raw_glosses": [
        "(firearms, transitive) To alter (a cartridge) by forcing it into a smaller calibre and size."
      ],
      "tags": [
        "transitive"
      ],
      "topics": [
        "engineering",
        "firearms",
        "government",
        "military",
        "natural-sciences",
        "physical-sciences",
        "politics",
        "tools",
        "war",
        "weaponry"
      ]
    }
  ],
  "word": "neck down"
}