"∇²" meaning in Translingual

{
  "etymology_templates": [
    {
      "args": {
        "1": "mul",
        "2": "∇⋅",
        "3": "∇"
      },
      "expansion": "∇⋅ + ∇",
      "name": "af"
    }
  ],
  "etymology_text": "∇⋅ + ∇",
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "∇²",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Translingual entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "mul",
          "name": "Mathematics",
          "orig": "mul:Mathematics",
          "parents": [
            "Formal sciences",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "the Laplacian differential operator; the divergence of the gradient"
      ],
      "id": "en-∇²-mul-symbol-t-wfu2XU",
      "links": [
        [
          "mathematics",
          "mathematics"
        ],
        [
          "Laplacian",
          "Laplacian"
        ],
        [
          "differential operator",
          "differential operator"
        ],
        [
          "divergence",
          "divergence"
        ],
        [
          "gradient",
          "gradient"
        ]
      ],
      "raw_glosses": [
        "(mathematics) the Laplacian differential operator; the divergence of the gradient"
      ],
      "topics": [
        "mathematics",
        "sciences"
      ]
    }
  ],
  "word": "∇²"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "mul",
        "2": "∇⋅",
        "3": "∇"
      },
      "expansion": "∇⋅ + ∇",
      "name": "af"
    }
  ],
  "etymology_text": "∇⋅ + ∇",
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "∇²",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        "Pages with 1 entry",
        "Pages with entries",
        "Translingual compound terms",
        "Translingual entries with incorrect language header",
        "Translingual lemmas",
        "Translingual symbols",
        "Translingual terms spelled with ²",
        "Translingual terms spelled with ∇",
        "mul:Mathematics"
      ],
      "glosses": [
        "the Laplacian differential operator; the divergence of the gradient"
      ],
      "links": [
        [
          "mathematics",
          "mathematics"
        ],
        [
          "Laplacian",
          "Laplacian"
        ],
        [
          "differential operator",
          "differential operator"
        ],
        [
          "divergence",
          "divergence"
        ],
        [
          "gradient",
          "gradient"
        ]
      ],
      "raw_glosses": [
        "(mathematics) the Laplacian differential operator; the divergence of the gradient"
      ],
      "topics": [
        "mathematics",
        "sciences"
      ]
    }
  ],
  "word": "∇²"
}