"relative pressure" meaning in English

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  "lang_code": "en",
  "pos": "noun",
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      "glosses": [
        "Synonym of gauge pressure"
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      "id": "en-relative_pressure-en-noun-TzT02wBb",
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          "gauge pressure",
          "gauge pressure#English"
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        "(physics, meteorology) Synonym of gauge pressure"
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          "word": "gauge pressure"
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  "word": "relative pressure"
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  "lang_code": "en",
  "pos": "noun",
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        "Synonym of gauge pressure"
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        "(physics, meteorology) Synonym of gauge pressure"
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          "word": "gauge pressure"
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  "word": "relative pressure"
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