"semiheavy water" meaning in English

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      "expansion": "semiheavy water (uncountable)",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "semi-heavy water"
        }
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      "glosses": [
        "Alternative spelling of semi-heavy water"
      ],
      "id": "en-semiheavy_water-en-noun-BM1BKDhi",
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  "word": "semiheavy water"
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{
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      "expansion": "semiheavy water (uncountable)",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "semi-heavy water"
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      "glosses": [
        "Alternative spelling of semi-heavy water"
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  "word": "semiheavy water"
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