"massa crítica" meaning in Portuguese

{
  "forms": [
    {
      "form": "massas críticas",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f"
      },
      "expansion": "massa crítica f (plural massas críticas)",
      "name": "pt-noun"
    }
  ],
  "lang": "Portuguese",
  "lang_code": "pt",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Portuguese entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "pt",
          "name": "Nuclear physics",
          "orig": "pt:Nuclear physics",
          "parents": [
            "Physics",
            "Quantum mechanics",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "pt",
          "name": "Nuclear warfare",
          "orig": "pt:Nuclear warfare",
          "parents": [
            "War",
            "Weapons",
            "Conflict",
            "Military",
            "Violence",
            "Hunting",
            "Tools",
            "Human behaviour",
            "Society",
            "Human activity",
            "Technology",
            "Human",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "critical mass (amount of fissile material needed to a nuclear chain reaction)"
      ],
      "id": "en-massa_crítica-pt-noun-sIwFd7es",
      "links": [
        [
          "nuclear physics",
          "nuclear physics"
        ],
        [
          "critical mass",
          "critical mass"
        ]
      ],
      "qualifier": "nuclear physics",
      "raw_glosses": [
        "(nuclear physics) critical mass (amount of fissile material needed to a nuclear chain reaction)"
      ],
      "tags": [
        "feminine"
      ]
    }
  ],
  "word": "massa crítica"
}

{
  "forms": [
    {
      "form": "massas críticas",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f"
      },
      "expansion": "massa crítica f (plural massas críticas)",
      "name": "pt-noun"
    }
  ],
  "lang": "Portuguese",
  "lang_code": "pt",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Portuguese countable nouns",
        "Portuguese entries with incorrect language header",
        "Portuguese feminine nouns",
        "Portuguese lemmas",
        "Portuguese multiword terms",
        "Portuguese nouns",
        "pt:Nuclear physics",
        "pt:Nuclear warfare"
      ],
      "glosses": [
        "critical mass (amount of fissile material needed to a nuclear chain reaction)"
      ],
      "links": [
        [
          "nuclear physics",
          "nuclear physics"
        ],
        [
          "critical mass",
          "critical mass"
        ]
      ],
      "qualifier": "nuclear physics",
      "raw_glosses": [
        "(nuclear physics) critical mass (amount of fissile material needed to a nuclear chain reaction)"
      ],
      "tags": [
        "feminine"
      ]
    }
  ],
  "word": "massa crítica"
}