"υστερ-" meaning in Greek

{
  "forms": [
    {
      "form": "yster-",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "el",
        "2": "prefix",
        "head": "",
        "sort": ""
      },
      "expansion": "υστερ- • (yster-)",
      "name": "head"
    },
    {
      "args": {},
      "expansion": "υστερ- • (yster-)",
      "name": "el-prefix"
    }
  ],
  "lang": "Greek",
  "lang_code": "el",
  "pos": "prefix",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "ystero-",
          "word": "υστερο-"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Greek entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Alternative form of υστερο- (ystero-)"
      ],
      "id": "en-υστερ--el-prefix-6AUra3Vu",
      "links": [
        [
          "υστερο-",
          "υστερο-#Greek"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative",
        "morpheme"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈisteɾ/"
    }
  ],
  "word": "υστερ-"
}

{
  "forms": [
    {
      "form": "yster-",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "el",
        "2": "prefix",
        "head": "",
        "sort": ""
      },
      "expansion": "υστερ- • (yster-)",
      "name": "head"
    },
    {
      "args": {},
      "expansion": "υστερ- • (yster-)",
      "name": "el-prefix"
    }
  ],
  "lang": "Greek",
  "lang_code": "el",
  "pos": "prefix",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "ystero-",
          "word": "υστερο-"
        }
      ],
      "categories": [
        "Greek entries with incorrect language header",
        "Greek lemmas",
        "Greek prefixes",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "Alternative form of υστερο- (ystero-)"
      ],
      "links": [
        [
          "υστερο-",
          "υστερο-#Greek"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative",
        "morpheme"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈisteɾ/"
    }
  ],
  "word": "υστερ-"
}