"birefringency" meaning in English

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      "expansion": "birefringency (uncountable)",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
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        {
          "word": "birefringence"
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      "glosses": [
        "Alternative form of birefringence"
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  "word": "birefringency"
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      "expansion": "birefringency (uncountable)",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
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        {
          "word": "birefringence"
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        "Alternative form of birefringence"
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  "word": "birefringency"
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