"0D" meaning in English

{
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      "args": {
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      "expansion": "0D (not comparable)",
      "name": "en-adj"
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  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "alt_of": [
        {
          "word": "zero-dimensional"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
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          "source": "w"
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          "parents": [
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          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Geometry",
          "orig": "en:Geometry",
          "parents": [
            "Mathematics",
            "Formal sciences",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Zero",
          "orig": "en:Zero",
          "parents": [
            "Numbers",
            "All topics",
            "Terms by semantic function",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Initialism of zero-dimensional."
      ],
      "id": "en-0D-en-adj-fqXKbbMz",
      "links": [
        [
          "zero-dimensional",
          "zero-dimensional#English"
        ]
      ],
      "synonyms": [
        {
          "word": "0d"
        },
        {
          "word": "0-D"
        },
        {
          "word": "0-d"
        }
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "initialism",
        "not-comparable"
      ]
    }
  ],
  "word": "0D"
}

{
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "0D (not comparable)",
      "name": "en-adj"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "alt_of": [
        {
          "word": "zero-dimensional"
        }
      ],
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        "English adjectives",
        "English entries with incorrect language header",
        "English initialisms",
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        "English terms spelled with numbers",
        "English uncomparable adjectives",
        "English words without vowels",
        "en:Geometry",
        "en:Zero"
      ],
      "glosses": [
        "Initialism of zero-dimensional."
      ],
      "links": [
        [
          "zero-dimensional",
          "zero-dimensional#English"
        ]
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "initialism",
        "not-comparable"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "0d"
    },
    {
      "word": "0-D"
    },
    {
      "word": "0-d"
    }
  ],
  "word": "0D"
}