fem·​to·​me·​ter | \ ˈfem(p)-tə-ˌmē-tər How to pronounce femtometer (audio) , -tō- \

Definition of femtometer

: a unit of length equal to 10−15 meters : one quadrillionth of a meter

Examples of femtometer in a Sentence

Recent Examples on the Web Finally, the results are in: Hessels and company have pegged the proton’s radius at 0.833 femtometers, give or take 0.01, a measurement exactly consistent with Pohl’s value. Quanta Magazine, "Physicists Finally Nail the Proton’s Size, and Hope Dies," 11 Sep. 2019 Pohl and his team were surprised to find a lower value for the radius, pegging it at 0.84 femtometer—well outside the range of potential sizes established by earlier measurements. Dan Falk, Scientific American, "Ultraprecise Measurement Pinpoints the Proton’s Size," 28 Nov. 2019 The result: their measurement of 0.833 femtometers (just under one-trillionth of a meter) agrees with the smaller value from the 2010 study. Jennifer Ouellette, Ars Technica, "Physics not “broken” after all? We’re close to resolving proton radius puzzle," 5 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'femtometer.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of femtometer

1971, in the meaning defined above

History and Etymology for femtometer

femto- + meter entry 3

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Time Traveler for femtometer

Time Traveler

The first known use of femtometer was in 1971

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Cite this Entry

“Femtometer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/femtometer. Accessed 26 Feb. 2021.

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