"absolute drought" meaning in English

{
  "forms": [
    {
      "form": "absolute droughts",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "absolute drought (plural absolute droughts)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "British English",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Climatology",
          "orig": "en:Climatology",
          "parents": [
            "Earth sciences",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A period of drought where there has been no precipitation for at least 15 days."
      ],
      "id": "en-absolute_drought-en-noun-sfhn0c-f",
      "links": [
        [
          "climatology",
          "climatology"
        ],
        [
          "drought",
          "drought"
        ],
        [
          "precipitation",
          "precipitation"
        ]
      ],
      "raw_glosses": [
        "(UK, climatology) A period of drought where there has been no precipitation for at least 15 days."
      ],
      "synonyms": [
        {
          "tags": [
            "US"
          ],
          "word": "dry spell"
        }
      ],
      "tags": [
        "UK"
      ],
      "topics": [
        "climatology",
        "natural-sciences"
      ]
    }
  ],
  "word": "absolute drought"
}

{
  "forms": [
    {
      "form": "absolute droughts",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "absolute drought (plural absolute droughts)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "British English",
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "en:Climatology"
      ],
      "glosses": [
        "A period of drought where there has been no precipitation for at least 15 days."
      ],
      "links": [
        [
          "climatology",
          "climatology"
        ],
        [
          "drought",
          "drought"
        ],
        [
          "precipitation",
          "precipitation"
        ]
      ],
      "raw_glosses": [
        "(UK, climatology) A period of drought where there has been no precipitation for at least 15 days."
      ],
      "tags": [
        "UK"
      ],
      "topics": [
        "climatology",
        "natural-sciences"
      ]
    }
  ],
  "synonyms": [
    {
      "tags": [
        "US"
      ],
      "word": "dry spell"
    }
  ],
  "word": "absolute drought"
}