"гидро-" meaning in Russe

{
  "categories": [
    {
      "kind": "other",
      "name": "Mots en russe issus d’un mot en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Préfixes en russe",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Russe",
      "orig": "russe",
      "parents": [],
      "source": "w"
    }
  ],
  "derived": [
    {
      "word": "гидробиология"
    },
    {
      "word": "гидрогеология"
    },
    {
      "word": "гидрометеорология"
    }
  ],
  "etymology_texts": [
    "Du grec ancien ὕδωρ, húdôr (« eau »)."
  ],
  "lang": "Russe",
  "lang_code": "ru",
  "pos": "prefix",
  "pos_title": "Préfixe",
  "senses": [
    {
      "glosses": [
        "Hydro-."
      ],
      "id": "fr-гидро--ru-prefix-rGvO7TjO"
    }
  ],
  "tags": [
    "morpheme"
  ],
  "word": "гидро-"
}

{
  "categories": [
    "Mots en russe issus d’un mot en grec ancien",
    "Préfixes en russe",
    "russe"
  ],
  "derived": [
    {
      "word": "гидробиология"
    },
    {
      "word": "гидрогеология"
    },
    {
      "word": "гидрометеорология"
    }
  ],
  "etymology_texts": [
    "Du grec ancien ὕδωρ, húdôr (« eau »)."
  ],
  "lang": "Russe",
  "lang_code": "ru",
  "pos": "prefix",
  "pos_title": "Préfixe",
  "senses": [
    {
      "glosses": [
        "Hydro-."
      ]
    }
  ],
  "tags": [
    "morpheme"
  ],
  "word": "гидро-"
}