"subcritical mass" meaning in English

{
  "antonyms": [
    {
      "word": "supercritical mass"
    }
  ],
  "forms": [
    {
      "form": "subcritical masses",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "subcritical mass (plural subcritical masses)",
      "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": "Nuclear warfare",
          "orig": "en:Nuclear warfare",
          "parents": [
            "War",
            "Weapons",
            "Conflict",
            "Military",
            "Violence",
            "Hunting",
            "Tools",
            "Human behaviour",
            "Society",
            "Human activity",
            "Technology",
            "Human",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Physics",
          "orig": "en:Physics",
          "parents": [
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Uranium",
          "orig": "en:Uranium",
          "parents": [
            "Actinide series chemical elements",
            "Chemical elements",
            "Metals",
            "Radioactivity",
            "Matter",
            "Metallurgy",
            "Nuclear physics",
            "Radiation",
            "Chemistry",
            "Nature",
            "Technology",
            "Physics",
            "Quantum mechanics",
            "Energy",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A mass of fissile material that is insufficient to sustain a nuclear chain reaction."
      ],
      "id": "en-subcritical_mass-en-noun-cEmL8n~9",
      "links": [
        [
          "physics",
          "physics"
        ],
        [
          "fissile",
          "fissile"
        ],
        [
          "nuclear",
          "nuclear"
        ],
        [
          "chain reaction",
          "chain reaction"
        ]
      ],
      "raw_glosses": [
        "(physics) A mass of fissile material that is insufficient to sustain a nuclear chain reaction."
      ],
      "topics": [
        "natural-sciences",
        "physical-sciences",
        "physics"
      ],
      "translations": [
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "insufficient mass to sustain chain reaction",
          "word": "alikriittinen massa"
        }
      ]
    }
  ],
  "word": "subcritical mass"
}

{
  "antonyms": [
    {
      "word": "supercritical mass"
    }
  ],
  "forms": [
    {
      "form": "subcritical masses",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "subcritical mass (plural subcritical masses)",
      "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:Nuclear warfare",
        "en:Physics",
        "en:Uranium"
      ],
      "glosses": [
        "A mass of fissile material that is insufficient to sustain a nuclear chain reaction."
      ],
      "links": [
        [
          "physics",
          "physics"
        ],
        [
          "fissile",
          "fissile"
        ],
        [
          "nuclear",
          "nuclear"
        ],
        [
          "chain reaction",
          "chain reaction"
        ]
      ],
      "raw_glosses": [
        "(physics) A mass of fissile material that is insufficient to sustain a nuclear chain reaction."
      ],
      "topics": [
        "natural-sciences",
        "physical-sciences",
        "physics"
      ]
    }
  ],
  "translations": [
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "insufficient mass to sustain chain reaction",
      "word": "alikriittinen massa"
    }
  ],
  "word": "subcritical mass"
}