"supplementary character" meaning in English

{
  "forms": [
    {
      "form": "supplementary characters",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "supplementary character (plural supplementary characters)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Computing",
          "orig": "en:Computing",
          "parents": [
            "Technology",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Any character assigned a code point in one of the supplementary planes (planes 1 through 16, covering the range U+10000 through U+10FFFF)."
      ],
      "id": "en-supplementary_character-en-noun-OiluKKC9",
      "links": [
        [
          "computing",
          "computing#Noun"
        ],
        [
          "code point",
          "code point"
        ],
        [
          "supplementary plane",
          "supplementary plane"
        ],
        [
          "plane",
          "plane"
        ]
      ],
      "qualifier": "Unicode",
      "raw_glosses": [
        "(computing, Unicode) Any character assigned a code point in one of the supplementary planes (planes 1 through 16, covering the range U+10000 through U+10FFFF)."
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ]
    }
  ],
  "word": "supplementary character"
}

{
  "forms": [
    {
      "form": "supplementary characters",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "supplementary character (plural supplementary characters)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "en:Computing"
      ],
      "glosses": [
        "Any character assigned a code point in one of the supplementary planes (planes 1 through 16, covering the range U+10000 through U+10FFFF)."
      ],
      "links": [
        [
          "computing",
          "computing#Noun"
        ],
        [
          "code point",
          "code point"
        ],
        [
          "supplementary plane",
          "supplementary plane"
        ],
        [
          "plane",
          "plane"
        ]
      ],
      "qualifier": "Unicode",
      "raw_glosses": [
        "(computing, Unicode) Any character assigned a code point in one of the supplementary planes (planes 1 through 16, covering the range U+10000 through U+10FFFF)."
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ]
    }
  ],
  "word": "supplementary character"
}