"double summer time" meaning in English

{
  "head_templates": [
    {
      "args": {
        "1": "-",
        "head": "double summer time"
      },
      "expansion": "double summer time (uncountable)",
      "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"
        }
      ],
      "examples": [
        {
          "ref": "1941 September, “Notes and News: Timetable Puzzles in Ireland”, in Railway Magazine, page 428",
          "text": "Double summertime in Ireland had some curious effects on timetables, seeing that in Eire the single additional hour only was worked to, whereas in Northern Ireland the full British two-hour addition was in operation.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "The advancing of clocks by two hours ahead of winter time in summer instead of the usual one hour; mainly used during World War II in the United Kingdom."
      ],
      "hyponyms": [
        {
          "word": "British Double Summer Time"
        }
      ],
      "id": "en-double_summer_time-en-noun-PveadlIz",
      "links": [
        [
          "winter time",
          "winter time"
        ],
        [
          "World War II",
          "World War II"
        ]
      ],
      "tags": [
        "uncountable"
      ]
    }
  ],
  "word": "double summer time"
}

{
  "head_templates": [
    {
      "args": {
        "1": "-",
        "head": "double summer time"
      },
      "expansion": "double summer time (uncountable)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with quotations",
        "English uncountable nouns"
      ],
      "examples": [
        {
          "ref": "1941 September, “Notes and News: Timetable Puzzles in Ireland”, in Railway Magazine, page 428",
          "text": "Double summertime in Ireland had some curious effects on timetables, seeing that in Eire the single additional hour only was worked to, whereas in Northern Ireland the full British two-hour addition was in operation.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "The advancing of clocks by two hours ahead of winter time in summer instead of the usual one hour; mainly used during World War II in the United Kingdom."
      ],
      "hyponyms": [
        {
          "word": "British Double Summer Time"
        }
      ],
      "links": [
        [
          "winter time",
          "winter time"
        ],
        [
          "World War II",
          "World War II"
        ]
      ],
      "tags": [
        "uncountable"
      ]
    }
  ],
  "word": "double summer time"
}