"-r" meaning in Turkish

{
  "forms": [
    {
      "form": "Post-vocalic form of",
      "head_nr": 2,
      "tags": [
        "canonical"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "tr",
        "2": "suffix form"
      },
      "expansion": "-r",
      "name": "head"
    },
    {
      "args": {
        "1": "-er",
        "2": "pv"
      },
      "expansion": "Post-vocalic form of -er.",
      "name": "tr-def-suffix form"
    }
  ],
  "lang": "Turkish",
  "lang_code": "tr",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 8 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Turkish entries with incorrect language header",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "oku(-mak) – okur"
        },
        {
          "text": "(to) read – he/she/it reads"
        }
      ],
      "glosses": [
        "Simple present tense suffix."
      ],
      "head_nr": 2,
      "id": "en--r-tr-suffix-vwJBRM3Q",
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-r"
}

{
  "forms": [
    {
      "form": "Post-vocalic form of",
      "head_nr": 2,
      "tags": [
        "canonical"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "tr",
        "2": "suffix form"
      },
      "expansion": "-r",
      "name": "head"
    },
    {
      "args": {
        "1": "-er",
        "2": "pv"
      },
      "expansion": "Post-vocalic form of -er.",
      "name": "tr-def-suffix form"
    }
  ],
  "lang": "Turkish",
  "lang_code": "tr",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        "Pages with 8 entries",
        "Pages with entries",
        "Turkish entries with incorrect language header",
        "Turkish non-lemma forms",
        "Turkish suffix forms"
      ],
      "examples": [
        {
          "text": "oku(-mak) – okur"
        },
        {
          "text": "(to) read – he/she/it reads"
        }
      ],
      "glosses": [
        "Simple present tense suffix."
      ],
      "head_nr": 2,
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-r"
}