"Rt△" meaning in Translingual

{
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    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "Rt△",
      "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"
        }
      ],
      "glosses": [
        "right triangle"
      ],
      "id": "en-Rt△-mul-symbol-9RgVXvsu",
      "links": [
        [
          "right triangle",
          "right triangle"
        ]
      ]
    }
  ],
  "word": "Rt△"
}

{
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "Rt△",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        "Pages with 1 entry",
        "Pages with entries",
        "Translingual entries with incorrect language header",
        "Translingual lemmas",
        "Translingual symbols",
        "Translingual terms spelled with △"
      ],
      "glosses": [
        "right triangle"
      ],
      "links": [
        [
          "right triangle",
          "right triangle"
        ]
      ]
    }
  ],
  "word": "Rt△"
}