"есөн" meaning in Mongolian

{
  "forms": [
    {
      "form": "jösön",
      "tags": [
        "romanization"
      ]
    },
    {
      "form": "ᠶᠢᠰᠦᠨ",
      "roman": "yisün",
      "tags": [
        "Mongolian"
      ]
    }
  ],
  "lang": "Mongolian",
  "lang_code": "mn",
  "pos": "num",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Mongolian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Mongolian terms with redundant script codes",
          "parents": [
            "Terms with redundant script codes",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "extra": "jes, “nine”",
          "word": "ес"
        }
      ],
      "glosses": [
        "oblique of ес (jes, “nine”)"
      ],
      "id": "en-есөн-mn-num-RzBcXl-2",
      "links": [
        [
          "ес",
          "ес#Mongolian"
        ],
        [
          "nine",
          "nine"
        ]
      ],
      "tags": [
        "form-of",
        "oblique"
      ]
    }
  ],
  "word": "есөн"
}

{
  "forms": [
    {
      "form": "jösön",
      "tags": [
        "romanization"
      ]
    },
    {
      "form": "ᠶᠢᠰᠦᠨ",
      "roman": "yisün",
      "tags": [
        "Mongolian"
      ]
    }
  ],
  "lang": "Mongolian",
  "lang_code": "mn",
  "pos": "num",
  "senses": [
    {
      "categories": [
        "Mongolian 2-syllable words",
        "Mongolian entries with incorrect language header",
        "Mongolian non-lemma forms",
        "Mongolian numeral forms",
        "Mongolian terms with redundant script codes",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "form_of": [
        {
          "extra": "jes, “nine”",
          "word": "ес"
        }
      ],
      "glosses": [
        "oblique of ес (jes, “nine”)"
      ],
      "links": [
        [
          "ес",
          "ес#Mongolian"
        ],
        [
          "nine",
          "nine"
        ]
      ],
      "tags": [
        "form-of",
        "oblique"
      ]
    }
  ],
  "word": "есөн"
}