"sŵ" meaning in Welsh

{
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "-"
      },
      "expansion": "sŵ m (uncountable, not mutable)",
      "name": "cy-noun"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "sw"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Welsh entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Misspelling of sw."
      ],
      "id": "en-sŵ-cy-noun-UodRJcG9",
      "links": [
        [
          "sw",
          "sw#Welsh"
        ]
      ],
      "tags": [
        "alt-of",
        "masculine",
        "misspelling",
        "not-mutable",
        "uncountable"
      ]
    }
  ],
  "word": "sŵ"
}

{
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "-"
      },
      "expansion": "sŵ m (uncountable, not mutable)",
      "name": "cy-noun"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "sw"
        }
      ],
      "categories": [
        "Pages with 1 entry",
        "Pages with entries",
        "Welsh entries with incorrect language header",
        "Welsh lemmas",
        "Welsh masculine nouns",
        "Welsh misspellings",
        "Welsh non-mutable terms",
        "Welsh nouns",
        "Welsh uncountable nouns"
      ],
      "glosses": [
        "Misspelling of sw."
      ],
      "links": [
        [
          "sw",
          "sw#Welsh"
        ]
      ],
      "tags": [
        "alt-of",
        "masculine",
        "misspelling",
        "not-mutable",
        "uncountable"
      ]
    }
  ],
  "word": "sŵ"
}