"roll cloud" meaning in English

{
  "etymology_text": "They usually appear to be \"rolling\" about a horizontal axis.",
  "forms": [
    {
      "form": "roll clouds",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "roll cloud (plural roll clouds)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Accessory clouds",
          "orig": "en:Accessory clouds",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Clouds",
          "orig": "en:Clouds",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Meteorology",
          "orig": "en:Meteorology",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "A low, horizontal, tube-shaped, and relatively rare type of arcus cloud, differing from shelf clouds by being completely detached from other cloud features."
      ],
      "id": "en-roll_cloud-en-noun-TIfWYhm7",
      "links": [
        [
          "meteorology",
          "meteorology"
        ],
        [
          "arcus",
          "arcus"
        ],
        [
          "shelf cloud",
          "shelf cloud"
        ]
      ],
      "raw_glosses": [
        "(meteorology) A low, horizontal, tube-shaped, and relatively rare type of arcus cloud, differing from shelf clouds by being completely detached from other cloud features."
      ],
      "topics": [
        "climatology",
        "meteorology",
        "natural-sciences"
      ]
    }
  ],
  "word": "roll cloud"
}

{
  "etymology_text": "They usually appear to be \"rolling\" about a horizontal axis.",
  "forms": [
    {
      "form": "roll clouds",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "roll cloud (plural roll clouds)",
      "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",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Accessory clouds",
        "en:Clouds",
        "en:Meteorology"
      ],
      "glosses": [
        "A low, horizontal, tube-shaped, and relatively rare type of arcus cloud, differing from shelf clouds by being completely detached from other cloud features."
      ],
      "links": [
        [
          "meteorology",
          "meteorology"
        ],
        [
          "arcus",
          "arcus"
        ],
        [
          "shelf cloud",
          "shelf cloud"
        ]
      ],
      "raw_glosses": [
        "(meteorology) A low, horizontal, tube-shaped, and relatively rare type of arcus cloud, differing from shelf clouds by being completely detached from other cloud features."
      ],
      "topics": [
        "climatology",
        "meteorology",
        "natural-sciences"
      ]
    }
  ],
  "word": "roll cloud"
}