"square circle" meaning in English

{
  "forms": [
    {
      "form": "square circles",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "square circle (plural square circles)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English oxymorons",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Philately",
          "orig": "en:Philately",
          "parents": [
            "Hobbies",
            "Recreation",
            "Human activity",
            "Human behaviour",
            "Human",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A cancellation mark consisting of an outer ring of concentric circles, cropped into a square shape."
      ],
      "id": "en-square_circle-en-noun-j48sBwlQ",
      "links": [
        [
          "philately",
          "philately"
        ],
        [
          "cancellation",
          "cancellation"
        ],
        [
          "mark",
          "mark"
        ],
        [
          "concentric",
          "concentric"
        ],
        [
          "crop",
          "crop"
        ]
      ],
      "raw_glosses": [
        "(philately) A cancellation mark consisting of an outer ring of concentric circles, cropped into a square shape."
      ],
      "related": [
        {
          "word": "squared circle"
        },
        {
          "word": "square the circle"
        }
      ],
      "topics": [
        "hobbies",
        "lifestyle",
        "philately"
      ]
    }
  ],
  "word": "square circle"
}

{
  "forms": [
    {
      "form": "square circles",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "square circle (plural square circles)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "squared circle"
    },
    {
      "word": "square the circle"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English oxymorons",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Philately"
      ],
      "glosses": [
        "A cancellation mark consisting of an outer ring of concentric circles, cropped into a square shape."
      ],
      "links": [
        [
          "philately",
          "philately"
        ],
        [
          "cancellation",
          "cancellation"
        ],
        [
          "mark",
          "mark"
        ],
        [
          "concentric",
          "concentric"
        ],
        [
          "crop",
          "crop"
        ]
      ],
      "raw_glosses": [
        "(philately) A cancellation mark consisting of an outer ring of concentric circles, cropped into a square shape."
      ],
      "topics": [
        "hobbies",
        "lifestyle",
        "philately"
      ]
    }
  ],
  "word": "square circle"
}