"masse critique" meaning in French

{
  "forms": [
    {
      "form": "masses critiques",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f"
      },
      "expansion": "masse critique f (plural masses critiques)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "French entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "fr",
          "name": "Nuclear warfare",
          "orig": "fr: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": "fr",
          "name": "Physics",
          "orig": "fr:Physics",
          "parents": [
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "critical mass (amount of fissile material needed to support a self-sustaining nuclear chain reaction)"
      ],
      "id": "en-masse_critique-fr-noun-j8uB5pTa",
      "links": [
        [
          "physics",
          "physics"
        ],
        [
          "critical mass",
          "critical mass"
        ]
      ],
      "raw_glosses": [
        "(physics) critical mass (amount of fissile material needed to support a self-sustaining nuclear chain reaction)"
      ],
      "tags": [
        "feminine"
      ],
      "topics": [
        "natural-sciences",
        "physical-sciences",
        "physics"
      ],
      "wikipedia": [
        "fr:masse critique"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/mas kʁi.tik/"
    }
  ],
  "word": "masse critique"
}

{
  "forms": [
    {
      "form": "masses critiques",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f"
      },
      "expansion": "masse critique f (plural masses critiques)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "French countable nouns",
        "French entries with incorrect language header",
        "French feminine nouns",
        "French lemmas",
        "French multiword terms",
        "French nouns",
        "French nouns with red links in their headword lines",
        "French terms with IPA pronunciation",
        "fr:Nuclear warfare",
        "fr:Physics"
      ],
      "glosses": [
        "critical mass (amount of fissile material needed to support a self-sustaining nuclear chain reaction)"
      ],
      "links": [
        [
          "physics",
          "physics"
        ],
        [
          "critical mass",
          "critical mass"
        ]
      ],
      "raw_glosses": [
        "(physics) critical mass (amount of fissile material needed to support a self-sustaining nuclear chain reaction)"
      ],
      "tags": [
        "feminine"
      ],
      "topics": [
        "natural-sciences",
        "physical-sciences",
        "physics"
      ],
      "wikipedia": [
        "fr:masse critique"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/mas kʁi.tik/"
    }
  ],
  "word": "masse critique"
}