"square engine" meaning in English

{
  "forms": [
    {
      "form": "square engines",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "square engine (plural square engines)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "_dis": "99 1",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "85 15",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "98 2",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "A U engine in which two parallel-twin engines are coupled together."
      ],
      "id": "en-square_engine-en-noun-UCuTVDRD",
      "links": [
        [
          "U engine",
          "U engine"
        ],
        [
          "parallel-twin engine",
          "parallel-twin engine"
        ],
        [
          "couple",
          "couple"
        ]
      ]
    },
    {
      "glosses": [
        "An engine with a stroke ratio of 1 (+/- 5%)."
      ],
      "id": "en-square_engine-en-noun-BCKN8Qhx"
    }
  ],
  "word": "square engine"
}

{
  "categories": [
    "English countable nouns",
    "English entries with incorrect language header",
    "English lemmas",
    "English multiword terms",
    "English nouns",
    "Pages with 1 entry",
    "Pages with entries"
  ],
  "forms": [
    {
      "form": "square engines",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "square engine (plural square engines)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "glosses": [
        "A U engine in which two parallel-twin engines are coupled together."
      ],
      "links": [
        [
          "U engine",
          "U engine"
        ],
        [
          "parallel-twin engine",
          "parallel-twin engine"
        ],
        [
          "couple",
          "couple"
        ]
      ]
    },
    {
      "glosses": [
        "An engine with a stroke ratio of 1 (+/- 5%)."
      ]
    }
  ],
  "word": "square engine"
}