"21.º" meaning in Spanish

{
  "forms": [
    {
      "form": "21.ª",
      "tags": [
        "feminine"
      ]
    },
    {
      "form": "21.ºs",
      "tags": [
        "masculine",
        "plural"
      ]
    },
    {
      "form": "21.ªs",
      "tags": [
        "feminine",
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "f": "21.ª",
        "fpl": "21.ªs",
        "mpl": "21.ºs"
      },
      "expansion": "21.º (feminine 21.ª, masculine plural 21.ºs, feminine plural 21.ªs)",
      "name": "es-adj"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "adj",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Spanish entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Spanish links with redundant alt parameters",
          "parents": [
            "Links with redundant alt parameters",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "21st; abbreviation of vigesimoprimero"
      ],
      "id": "en-21.º-es-adj-DC4SlIGP",
      "links": [
        [
          "21st",
          "21st"
        ],
        [
          "vigesimoprimero",
          "vigesimoprimero#Spanish"
        ]
      ]
    }
  ],
  "word": "21.º"
}

{
  "forms": [
    {
      "form": "21.ª",
      "tags": [
        "feminine"
      ]
    },
    {
      "form": "21.ºs",
      "tags": [
        "masculine",
        "plural"
      ]
    },
    {
      "form": "21.ªs",
      "tags": [
        "feminine",
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "f": "21.ª",
        "fpl": "21.ªs",
        "mpl": "21.ºs"
      },
      "expansion": "21.º (feminine 21.ª, masculine plural 21.ºs, feminine plural 21.ªs)",
      "name": "es-adj"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "adj",
  "senses": [
    {
      "categories": [
        "Pages with 1 entry",
        "Pages with entries",
        "Spanish abbreviations",
        "Spanish adjectives",
        "Spanish adjectives with red links in their headword lines",
        "Spanish entries with incorrect language header",
        "Spanish lemmas",
        "Spanish links with redundant alt parameters",
        "Spanish terms spelled with .",
        "Spanish terms spelled with numbers",
        "Spanish terms spelled with º"
      ],
      "glosses": [
        "21st; abbreviation of vigesimoprimero"
      ],
      "links": [
        [
          "21st",
          "21st"
        ],
        [
          "vigesimoprimero",
          "vigesimoprimero#Spanish"
        ]
      ]
    }
  ],
  "word": "21.º"
}