"atto-" meaning in Catalan

{
  "etymology_templates": [
    {
      "args": {
        "1": "ca",
        "2": "da",
        "3": "atten",
        "4": "",
        "5": "eighteen"
      },
      "expansion": "Borrowed from Danish atten (“eighteen”)",
      "name": "bor+"
    }
  ],
  "etymology_text": "Borrowed from Danish atten (“eighteen”).",
  "head_templates": [
    {
      "args": {
        "1": "ca",
        "2": "prefix"
      },
      "expansion": "atto-",
      "name": "head"
    }
  ],
  "lang": "Catalan",
  "lang_code": "ca",
  "pos": "prefix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Catalan entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 8 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "ca",
          "name": "SI units",
          "orig": "ca:SI units",
          "parents": [
            "Units of measure",
            "Metrology",
            "Quantity",
            "Applied sciences",
            "Mathematics",
            "Sciences",
            "Formal sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "atto-"
      ],
      "id": "en-atto--ca-prefix-1MKbhLV0",
      "links": [
        [
          "atto-",
          "atto-#English"
        ]
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "atto-"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "ca",
        "2": "da",
        "3": "atten",
        "4": "",
        "5": "eighteen"
      },
      "expansion": "Borrowed from Danish atten (“eighteen”)",
      "name": "bor+"
    }
  ],
  "etymology_text": "Borrowed from Danish atten (“eighteen”).",
  "head_templates": [
    {
      "args": {
        "1": "ca",
        "2": "prefix"
      },
      "expansion": "atto-",
      "name": "head"
    }
  ],
  "lang": "Catalan",
  "lang_code": "ca",
  "pos": "prefix",
  "senses": [
    {
      "categories": [
        "Catalan entries with incorrect language header",
        "Catalan lemmas",
        "Catalan prefixes",
        "Catalan terms borrowed from Danish",
        "Catalan terms derived from Danish",
        "Pages with 8 entries",
        "Pages with entries",
        "ca:SI units"
      ],
      "glosses": [
        "atto-"
      ],
      "links": [
        [
          "atto-",
          "atto-#English"
        ]
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "atto-"
}