"actino-" meaning in Translingual

{
  "etymology_templates": [
    {
      "args": {
        "1": "mul",
        "2": "grc",
        "3": "-"
      },
      "expansion": "Ancient Greek",
      "name": "der"
    }
  ],
  "etymology_text": "From Ancient Greek, the stem of ἀκτίς (aktís, “ray”).",
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "prefix"
      },
      "expansion": "actino-",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "prefix",
  "senses": [
    {
      "categories": [
        {
          "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"
        }
      ],
      "derived": [
        {
          "word": "Actinobacteria"
        },
        {
          "word": "Actinopterygii"
        },
        {
          "word": "Actinodura"
        },
        {
          "word": "Actinote"
        },
        {
          "word": "Actinomyces"
        }
      ],
      "glosses": [
        "ray; radial form"
      ],
      "id": "en-actino--mul-prefix-O7H19Lwx",
      "links": [
        [
          "ray",
          "ray"
        ],
        [
          "radial",
          "radial"
        ]
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "actino-"
}

{
  "derived": [
    {
      "word": "Actinobacteria"
    },
    {
      "word": "Actinopterygii"
    },
    {
      "word": "Actinodura"
    },
    {
      "word": "Actinote"
    },
    {
      "word": "Actinomyces"
    }
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "mul",
        "2": "grc",
        "3": "-"
      },
      "expansion": "Ancient Greek",
      "name": "der"
    }
  ],
  "etymology_text": "From Ancient Greek, the stem of ἀκτίς (aktís, “ray”).",
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "prefix"
      },
      "expansion": "actino-",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "prefix",
  "senses": [
    {
      "categories": [
        "Pages with 4 entries",
        "Pages with entries",
        "Translingual entries with incorrect language header",
        "Translingual lemmas",
        "Translingual prefixes",
        "Translingual terms derived from Ancient Greek"
      ],
      "glosses": [
        "ray; radial form"
      ],
      "links": [
        [
          "ray",
          "ray"
        ],
        [
          "radial",
          "radial"
        ]
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "actino-"
}