"-үс" meaning in Yakut

{
  "forms": [
    {
      "form": "-üs",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sah",
        "2": "suffixes"
      },
      "expansion": "-үс • (-üs)",
      "name": "head"
    }
  ],
  "lang": "Yakut",
  "lang_code": "sah",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Yakut entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "derived": [
        {
          "english": "third",
          "roman": "ühüs",
          "word": "үһүс"
        },
        {
          "english": "fourth",
          "roman": "tördüs",
          "word": "төрдүс"
        }
      ],
      "glosses": [
        "Attaches to numerals to form ordinal numbers."
      ],
      "id": "en--үс-sah-suffix-nxoVuynu",
      "related": [
        {
          "roman": "-is",
          "word": "-ис"
        },
        {
          "roman": "-ıs",
          "word": "-ыс"
        },
        {
          "roman": "-us",
          "word": "-ус"
        }
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-үс"
}

{
  "derived": [
    {
      "english": "third",
      "roman": "ühüs",
      "word": "үһүс"
    },
    {
      "english": "fourth",
      "roman": "tördüs",
      "word": "төрдүс"
    }
  ],
  "forms": [
    {
      "form": "-üs",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sah",
        "2": "suffixes"
      },
      "expansion": "-үс • (-üs)",
      "name": "head"
    }
  ],
  "lang": "Yakut",
  "lang_code": "sah",
  "pos": "suffix",
  "related": [
    {
      "roman": "-is",
      "word": "-ис"
    },
    {
      "roman": "-ıs",
      "word": "-ыс"
    },
    {
      "roman": "-us",
      "word": "-ус"
    }
  ],
  "senses": [
    {
      "categories": [
        "Pages with 1 entry",
        "Pages with entries",
        "Yakut entries with incorrect language header",
        "Yakut lemmas",
        "Yakut suffixes",
        "Yakut vowel harmonic lemmas"
      ],
      "glosses": [
        "Attaches to numerals to form ordinal numbers."
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-үс"
}

{
  "called_from": "form_descriptions/1698",
  "msg": "unrecognized head form: complying with vowel harmony",
  "path": [
    "-үс"
  ],
  "section": "Yakut",
  "subsection": "suffix",
  "title": "-үс",
  "trace": ""
}