"square femtometre" meaning in Anglais

{
  "categories": [
    {
      "kind": "other",
      "name": "Locutions nominales en anglais",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Unités de mesure en anglais",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Anglais",
      "orig": "anglais",
      "parents": [],
      "source": "w"
    }
  ],
  "forms": [
    {
      "form": "square femtometres",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "square femtometer",
      "raw_tags": [
        "États-Unis"
      ]
    }
  ],
  "lang": "Anglais",
  "lang_code": "en",
  "pos": "noun",
  "pos_title": "Locution nominale",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Anglais du Royaume-Uni",
          "orig": "anglais du Royaume-Uni",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Femtomètre carré (fm²)."
      ],
      "id": "fr-square_femtometre-en-noun-644BhskI",
      "raw_tags": [
        "Royaume-Uni"
      ],
      "topics": [
        "metrology"
      ]
    }
  ],
  "word": "square femtometre"
}

{
  "categories": [
    "Locutions nominales en anglais",
    "Unités de mesure en anglais",
    "anglais"
  ],
  "forms": [
    {
      "form": "square femtometres",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "square femtometer",
      "raw_tags": [
        "États-Unis"
      ]
    }
  ],
  "lang": "Anglais",
  "lang_code": "en",
  "pos": "noun",
  "pos_title": "Locution nominale",
  "senses": [
    {
      "categories": [
        "anglais du Royaume-Uni"
      ],
      "glosses": [
        "Femtomètre carré (fm²)."
      ],
      "raw_tags": [
        "Royaume-Uni"
      ],
      "topics": [
        "metrology"
      ]
    }
  ],
  "word": "square femtometre"
}