"eu-" meaning in Translingual

{
  "etymology_templates": [
    {
      "args": {
        "1": "mul",
        "2": "NL.",
        "3": "-"
      },
      "expansion": "New Latin",
      "name": "der"
    },
    {
      "args": {
        "1": "mul",
        "2": "grc",
        "3": "εὖ",
        "4": "",
        "5": "well, good"
      },
      "expansion": "Ancient Greek εὖ (eû, “well, good”)",
      "name": "der"
    }
  ],
  "etymology_text": "New Latin, from Ancient Greek εὖ (eû, “well, good”)",
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "prefix"
      },
      "expansion": "eu-",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "prefix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages using catfix",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 4 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Translingual entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Used to form taxonomic names corresponding to English vernacular names beginning with true"
      ],
      "id": "en-eu--mul-prefix-2-HzO8~8",
      "links": [
        [
          "true",
          "true#English"
        ]
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "eu-"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "mul",
        "2": "NL.",
        "3": "-"
      },
      "expansion": "New Latin",
      "name": "der"
    },
    {
      "args": {
        "1": "mul",
        "2": "grc",
        "3": "εὖ",
        "4": "",
        "5": "well, good"
      },
      "expansion": "Ancient Greek εὖ (eû, “well, good”)",
      "name": "der"
    }
  ],
  "etymology_text": "New Latin, from Ancient Greek εὖ (eû, “well, good”)",
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "prefix"
      },
      "expansion": "eu-",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "prefix",
  "senses": [
    {
      "categories": [
        "Pages using catfix",
        "Pages with 4 entries",
        "Pages with entries",
        "Translingual entries with incorrect language header",
        "Translingual lemmas",
        "Translingual prefixes",
        "Translingual terms derived from Ancient Greek",
        "Translingual terms derived from New Latin"
      ],
      "glosses": [
        "Used to form taxonomic names corresponding to English vernacular names beginning with true"
      ],
      "links": [
        [
          "true",
          "true#English"
        ]
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "eu-"
}