"vilsă" meaning in Polabian

{
  "etymology_templates": [
    {
      "args": {
        "1": "pox",
        "2": "sla-pro",
        "3": "*èlьša"
      },
      "expansion": "Proto-Slavic *èlьša",
      "name": "inh"
    }
  ],
  "etymology_text": "From Proto-Slavic *èlьša.",
  "head_templates": [
    {
      "args": {
        "1": "f"
      },
      "expansion": "vilsă f",
      "name": "pox-noun"
    }
  ],
  "lang": "Polabian",
  "lang_code": "pox",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Polabian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "lifeform",
          "langcode": "pox",
          "name": "Birch family plants",
          "orig": "pox:Birch family plants",
          "parents": [
            "Fagales order plants",
            "Plants",
            "Shrubs",
            "Trees",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "alder"
      ],
      "id": "en-vilsă-pox-noun-vy0TwJyn",
      "links": [
        [
          "alder",
          "alder"
        ]
      ],
      "tags": [
        "feminine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈvilsɐ/"
    }
  ],
  "word": "vilsă"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "pox",
        "2": "sla-pro",
        "3": "*èlьša"
      },
      "expansion": "Proto-Slavic *èlьša",
      "name": "inh"
    }
  ],
  "etymology_text": "From Proto-Slavic *èlьša.",
  "head_templates": [
    {
      "args": {
        "1": "f"
      },
      "expansion": "vilsă f",
      "name": "pox-noun"
    }
  ],
  "lang": "Polabian",
  "lang_code": "pox",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Polabian entries with incorrect language header",
        "Polabian feminine nouns",
        "Polabian lemmas",
        "Polabian nouns",
        "Polabian terms derived from Proto-Slavic",
        "Polabian terms inherited from Proto-Slavic",
        "Polabian terms with IPA pronunciation",
        "pox:Birch family plants"
      ],
      "glosses": [
        "alder"
      ],
      "links": [
        [
          "alder",
          "alder"
        ]
      ],
      "tags": [
        "feminine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈvilsɐ/"
    }
  ],
  "word": "vilsă"
}