"半減期" meaning in Japanese

{
  "forms": [
    {
      "form": "半減期",
      "ruby": [
        [
          "半",
          "はん"
        ],
        [
          "減",
          "げん"
        ],
        [
          "期",
          "き"
        ]
      ],
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "hangenki",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "はんげんき"
      },
      "expansion": "半(はん)減(げん)期(き) • (hangenki)",
      "name": "ja-noun"
    }
  ],
  "lang": "Japanese",
  "lang_code": "ja",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Japanese entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Japanese links with redundant wikilinks",
          "parents": [
            "Links with redundant wikilinks",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Japanese terms prefixed with 半",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Japanese terms with redundant sortkeys",
          "parents": [
            "Terms with redundant sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "ja",
          "name": "Chemistry",
          "orig": "ja:Chemistry",
          "parents": [
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "ja",
          "name": "Medicine",
          "orig": "ja:Medicine",
          "parents": [
            "Biology",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "ja",
          "name": "Physics",
          "orig": "ja:Physics",
          "parents": [
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "a half-life"
      ],
      "id": "en-半減期-ja-noun-YT3LOUSJ",
      "links": [
        [
          "physics",
          "physics"
        ],
        [
          "chemistry",
          "chemistry"
        ],
        [
          "medicine",
          "medicine"
        ],
        [
          "half-life",
          "half-life"
        ]
      ],
      "raw_glosses": [
        "(physics, chemistry, medicine) a half-life"
      ],
      "topics": [
        "chemistry",
        "medicine",
        "natural-sciences",
        "physical-sciences",
        "physics",
        "sciences"
      ],
      "wikipedia": [
        "ja:半減期"
      ]
    }
  ],
  "sounds": [
    {
      "other": "はんげんき"
    },
    {
      "ipa": "[hã̠ŋɡẽ̞ŋʲkʲi]"
    }
  ],
  "word": "半減期"
}

{
  "forms": [
    {
      "form": "半減期",
      "ruby": [
        [
          "半",
          "はん"
        ],
        [
          "減",
          "げん"
        ],
        [
          "期",
          "き"
        ]
      ],
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "hangenki",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "はんげんき"
      },
      "expansion": "半(はん)減(げん)期(き) • (hangenki)",
      "name": "ja-noun"
    }
  ],
  "lang": "Japanese",
  "lang_code": "ja",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Japanese entries with incorrect language header",
        "Japanese lemmas",
        "Japanese links with redundant wikilinks",
        "Japanese nouns",
        "Japanese terms prefixed with 半",
        "Japanese terms spelled with fifth grade kanji",
        "Japanese terms spelled with second grade kanji",
        "Japanese terms spelled with third grade kanji",
        "Japanese terms with IPA pronunciation",
        "Japanese terms with redundant sortkeys",
        "Japanese terms written with three Han script characters",
        "ja:Chemistry",
        "ja:Medicine",
        "ja:Physics"
      ],
      "glosses": [
        "a half-life"
      ],
      "links": [
        [
          "physics",
          "physics"
        ],
        [
          "chemistry",
          "chemistry"
        ],
        [
          "medicine",
          "medicine"
        ],
        [
          "half-life",
          "half-life"
        ]
      ],
      "raw_glosses": [
        "(physics, chemistry, medicine) a half-life"
      ],
      "topics": [
        "chemistry",
        "medicine",
        "natural-sciences",
        "physical-sciences",
        "physics",
        "sciences"
      ],
      "wikipedia": [
        "ja:半減期"
      ]
    }
  ],
  "sounds": [
    {
      "other": "はんげんき"
    },
    {
      "ipa": "[hã̠ŋɡẽ̞ŋʲkʲi]"
    }
  ],
  "word": "半減期"
}