"-u" meaning in Ido

{
  "etymology_templates": [
    {
      "args": {
        "1": "io",
        "2": "fr",
        "3": "tu"
      },
      "expansion": "French tu",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "it",
        "3": "tu"
      },
      "expansion": "Italian tu",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "es",
        "3": "tú"
      },
      "expansion": "Spanish tú",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "fr",
        "3": "vous"
      },
      "expansion": "French vous",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "it",
        "3": "voi"
      },
      "expansion": "Italian voi",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "es",
        "3": "vos"
      },
      "expansion": "Spanish vos",
      "name": "bor"
    }
  ],
  "etymology_text": "Common vowel found in pronouns in Romance languages: French tu, Italian tu and Spanish tú, also in French vous and as an o in Italian voi and Spanish vos, etc. (Compare tu and vu)",
  "head_templates": [
    {
      "args": {
        "1": "io",
        "2": "suffix"
      },
      "expansion": "-u",
      "name": "head"
    }
  ],
  "lang": "Ido",
  "lang_code": "io",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Ido entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 24 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "omna (“all, every”) + -u → omnu (“everyone”)",
          "type": "example"
        }
      ],
      "glosses": [
        "suffix used to form pronouns indicating a person"
      ],
      "id": "en--u-io-suffix-xiFDogRu",
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-u"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "io",
        "2": "fr",
        "3": "tu"
      },
      "expansion": "French tu",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "it",
        "3": "tu"
      },
      "expansion": "Italian tu",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "es",
        "3": "tú"
      },
      "expansion": "Spanish tú",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "fr",
        "3": "vous"
      },
      "expansion": "French vous",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "it",
        "3": "voi"
      },
      "expansion": "Italian voi",
      "name": "bor"
    },
    {
      "args": {
        "1": "io",
        "2": "es",
        "3": "vos"
      },
      "expansion": "Spanish vos",
      "name": "bor"
    }
  ],
  "etymology_text": "Common vowel found in pronouns in Romance languages: French tu, Italian tu and Spanish tú, also in French vous and as an o in Italian voi and Spanish vos, etc. (Compare tu and vu)",
  "head_templates": [
    {
      "args": {
        "1": "io",
        "2": "suffix"
      },
      "expansion": "-u",
      "name": "head"
    }
  ],
  "lang": "Ido",
  "lang_code": "io",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        "Ido entries with incorrect language header",
        "Ido lemmas",
        "Ido suffixes",
        "Ido terms borrowed from French",
        "Ido terms borrowed from Italian",
        "Ido terms borrowed from Spanish",
        "Ido terms derived from French",
        "Ido terms derived from Italian",
        "Ido terms derived from Spanish",
        "Pages with 24 entries",
        "Pages with entries"
      ],
      "examples": [
        {
          "text": "omna (“all, every”) + -u → omnu (“everyone”)",
          "type": "example"
        }
      ],
      "glosses": [
        "suffix used to form pronouns indicating a person"
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-u"
}