"ground swell" meaning in English

{
  "forms": [
    {
      "form": "ground swells",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ground swell (plural ground swells)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "groundswell"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1999 September 26, “Blair: doing well, could do better”, in The Guardian",
          "text": "This is reflected in the ground swell of unease and criticism reported by our opinion poll evidence this morning, and in recent election results, such as those last week in Hamilton and Wigan.",
          "type": "quotation"
        },
        {
          "ref": "2005, Matt Warshaw, The Encyclopedia of Surfing, page 239",
          "text": "Beachbreaks excepted, ground swells generally produce high-quality surf.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Alternative form of groundswell"
      ],
      "id": "en-ground_swell-en-noun-J22-3tBc",
      "links": [
        [
          "groundswell",
          "groundswell#English"
        ]
      ],
      "related": [
        {
          "word": "wind swell"
        }
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "ground swell"
}

{
  "forms": [
    {
      "form": "ground swells",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ground swell (plural ground swells)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "wind swell"
    }
  ],
  "senses": [
    {
      "alt_of": [
        {
          "word": "groundswell"
        }
      ],
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with quotations"
      ],
      "examples": [
        {
          "ref": "1999 September 26, “Blair: doing well, could do better”, in The Guardian",
          "text": "This is reflected in the ground swell of unease and criticism reported by our opinion poll evidence this morning, and in recent election results, such as those last week in Hamilton and Wigan.",
          "type": "quotation"
        },
        {
          "ref": "2005, Matt Warshaw, The Encyclopedia of Surfing, page 239",
          "text": "Beachbreaks excepted, ground swells generally produce high-quality surf.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Alternative form of groundswell"
      ],
      "links": [
        [
          "groundswell",
          "groundswell#English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "ground swell"
}