"bu" meaning in Upper Sorbian

{
  "head_templates": [
    {
      "args": {
        "1": "hsb",
        "2": "verb form"
      },
      "expansion": "bu",
      "name": "head"
    }
  ],
  "lang": "Upper Sorbian",
  "lang_code": "hsb",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 60 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Upper Sorbian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "word": "być"
        }
      ],
      "glosses": [
        "second/third-person singular passive of być"
      ],
      "id": "en-bu-hsb-verb-wIq1SVq9",
      "links": [
        [
          "być",
          "być#Upper_Sorbian"
        ]
      ],
      "tags": [
        "form-of",
        "passive",
        "second-person",
        "singular",
        "third-person"
      ]
    }
  ],
  "word": "bu"
}

{
  "categories": [
    "Pages with 60 entries",
    "Pages with entries",
    "zom:Animal dwellings",
    "zom:Buildings",
    "zom:Foods"
  ],
  "head_templates": [
    {
      "args": {
        "1": "hsb",
        "2": "verb form"
      },
      "expansion": "bu",
      "name": "head"
    }
  ],
  "lang": "Upper Sorbian",
  "lang_code": "hsb",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        "Pages with 60 entries",
        "Pages with entries",
        "Upper Sorbian entries with incorrect language header",
        "Upper Sorbian non-lemma forms",
        "Upper Sorbian verb forms"
      ],
      "form_of": [
        {
          "word": "być"
        }
      ],
      "glosses": [
        "second/third-person singular passive of być"
      ],
      "links": [
        [
          "być",
          "być#Upper_Sorbian"
        ]
      ],
      "tags": [
        "form-of",
        "passive",
        "second-person",
        "singular",
        "third-person"
      ]
    }
  ],
  "word": "bu"
}