"сткло" meaning in Old Church Slavonic

{
  "forms": [
    {
      "form": "stklo",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "cu",
        "2": "noun"
      },
      "expansion": "сткло • (stklo)",
      "name": "head"
    }
  ],
  "lang": "Old Church Slavonic",
  "lang_code": "cu",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "stĭklo",
          "word": "стькло"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Old Church Slavonic entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "roman": "[…] I stogny gradu zlato čisto, jako stklo presvětlo.",
          "text": "[…] И стогны граду злато чисто, яко сткло пресвѣтло.",
          "type": "example"
        },
        {
          "type": "example"
        }
      ],
      "glosses": [
        "Alternative form of стькло (stĭklo)"
      ],
      "id": "en-сткло-cu-noun-W~7d4qog",
      "links": [
        [
          "стькло",
          "стькло#Old_Church_Slavonic"
        ]
      ],
      "tags": [
        "Old-East-Church-Slavonic",
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "сткло"
}

{
  "forms": [
    {
      "form": "stklo",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "cu",
        "2": "noun"
      },
      "expansion": "сткло • (stklo)",
      "name": "head"
    }
  ],
  "lang": "Old Church Slavonic",
  "lang_code": "cu",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "stĭklo",
          "word": "стькло"
        }
      ],
      "categories": [
        "Old Church Slavonic entries with incorrect language header",
        "Old Church Slavonic lemmas",
        "Old Church Slavonic nouns",
        "Old Church Slavonic terms with quotations",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "roman": "[…] I stogny gradu zlato čisto, jako stklo presvětlo.",
          "text": "[…] И стогны граду злато чисто, яко сткло пресвѣтло.",
          "type": "example"
        },
        {
          "type": "example"
        }
      ],
      "glosses": [
        "Alternative form of стькло (stĭklo)"
      ],
      "links": [
        [
          "стькло",
          "стькло#Old_Church_Slavonic"
        ]
      ],
      "tags": [
        "Old-East-Church-Slavonic",
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "сткло"
}