"reserved word" meaning in English

{
  "etymology_text": "reserved word < → δείτε τις λέξεις reserved και word",
  "forms": [
    {
      "form": "reserved word"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Προγραμματισμός (αγγλικά)",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "δεσμευμένη λέξη"
      ],
      "id": "el-reserved_word-en-noun-Ayvcb9LU",
      "raw_tags": [
        "προγραμματισμός"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "keyword"
    },
    {
      "word": "C"
    },
    {
      "word": "Python"
    },
    {
      "word": "reserved identifier"
    }
  ],
  "word": "reserved word"
}

{
  "etymology_text": "reserved word < → δείτε τις λέξεις reserved και word",
  "forms": [
    {
      "form": "reserved word"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Προγραμματισμός (αγγλικά)"
      ],
      "glosses": [
        "δεσμευμένη λέξη"
      ],
      "raw_tags": [
        "προγραμματισμός"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "keyword"
    },
    {
      "word": "C"
    },
    {
      "word": "Python"
    },
    {
      "word": "reserved identifier"
    }
  ],
  "word": "reserved word"
}