"femtometer" meaning in English

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        "2": "femto",
        "3": "meter"
      },
      "expansion": "femto- + meter",
      "name": "prefix"
    }
  ],
  "etymology_text": "femto- + meter",
  "forms": [
    {
      "form": "femtometers",
      "tags": [
        "plural"
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  "head_templates": [
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  "lang_code": "en",
  "pos": "noun",
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      "alt_of": [
        {
          "word": "femtometre"
        }
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          "kind": "other",
          "name": "American English",
          "parents": [],
          "source": "w"
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          "orig": "en:Physics",
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        },
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          "kind": "topical",
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          "name": "SI units",
          "orig": "en:SI units",
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            "Units of measure",
            "Metrology",
            "Quantity",
            "Applied sciences",
            "Mathematics",
            "Sciences",
            "Formal sciences",
            "All topics",
            "Fundamental"
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          "source": "w"
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      ],
      "glosses": [
        "US spelling of femtometre."
      ],
      "id": "en-femtometer-en-noun-prStGVAv",
      "links": [
        [
          "femtometre",
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        ]
      ],
      "tags": [
        "US",
        "alt-of"
      ]
    }
  ],
  "word": "femtometer"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "femto",
        "3": "meter"
      },
      "expansion": "femto- + meter",
      "name": "prefix"
    }
  ],
  "etymology_text": "femto- + meter",
  "forms": [
    {
      "form": "femtometers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
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      "args": {},
      "expansion": "femtometer (plural femtometers)",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "femtometre"
        }
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      "glosses": [
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  "word": "femtometer"
}