"-∅" meaning in Russian

{
  "head_templates": [
    {
      "args": {
        "1": "ru",
        "2": "suffix"
      },
      "expansion": "-∅",
      "name": "head"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Russian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Russian links with redundant target parameters",
          "parents": [
            "Links with redundant target parameters",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Russian terms in nonstandard scripts",
          "parents": [
            "Terms in nonstandard scripts",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "кни́га (kníga, “book”) + -∅ → книг (knig, “…of [the] books”)",
          "type": "example"
        },
        {
          "text": "ме́сто (mésto, “place”) + -∅ → мест (mest, “…of [the] places”)",
          "type": "example"
        }
      ],
      "glosses": [
        "Indicates the genitive plural of first-declension and neuter second-declension nouns:",
        "Indicates the genitive plural of first-declension and neuter second-declension nouns"
      ],
      "id": "en--∅-ru-suffix-CGENsHuE",
      "links": [
        [
          "genitive",
          "genitive#English"
        ],
        [
          "first-declension",
          "w:Russian_declension#First_declension"
        ],
        [
          "neuter second-declension",
          "w:Russian_declension#Second_declension_–_neuter_nouns"
        ]
      ],
      "raw_glosses": [
        "Indicates the genitive plural of first-declension and neuter second-declension nouns:"
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-∅"
}

{
  "head_templates": [
    {
      "args": {
        "1": "ru",
        "2": "suffix"
      },
      "expansion": "-∅",
      "name": "head"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        "Russian entries with incorrect language header",
        "Russian lemmas",
        "Russian links with redundant target parameters",
        "Russian suffixes",
        "Russian terms in nonstandard scripts"
      ],
      "examples": [
        {
          "text": "кни́га (kníga, “book”) + -∅ → книг (knig, “…of [the] books”)",
          "type": "example"
        },
        {
          "text": "ме́сто (mésto, “place”) + -∅ → мест (mest, “…of [the] places”)",
          "type": "example"
        }
      ],
      "glosses": [
        "Indicates the genitive plural of first-declension and neuter second-declension nouns:",
        "Indicates the genitive plural of first-declension and neuter second-declension nouns"
      ],
      "links": [
        [
          "genitive",
          "genitive#English"
        ],
        [
          "first-declension",
          "w:Russian_declension#First_declension"
        ],
        [
          "neuter second-declension",
          "w:Russian_declension#Second_declension_–_neuter_nouns"
        ]
      ],
      "raw_glosses": [
        "Indicates the genitive plural of first-declension and neuter second-declension nouns:"
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-∅"
}