femtosecond

noun

fem·​to·​sec·​ond ˈfem(p)-tə-ˌse-kənd How to pronounce femtosecond (audio)
-kənt, 
-tō-
: one quadrillionth of a second

Examples of femtosecond in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
That’s like trying to measure a 100-meter Olympic race on a femtosecond timescale. — Philipp Strasberg, Scientific American, 20 Oct. 2026 The project represents a €6 million (approximately $6,740,400) investment to develop femtosecond lasers. — Mrigakshi Dixit, Interesting Engineering, 20 Oct. 2026 The authors calculate that the transition from reflective to transmission needs to take place in about 10 femtoseconds (a femtosecond is 10-15 s), which is insufficient time to move a physical mirror. — Chris Lee, ArsTechnica, 22 July 2026 The new prototype, still very far from being practical, took femtoseconds (quadrillionths of a second) to charge and stored the energy for nanoseconds. — New Atlas, 4 Apr. 2026 See All Example Sentences for femtosecond

Word History

First Known Use

1976, in the meaning defined above

Time Traveler
The first known use of femtosecond was in 1976

Rhymes for femtosecond

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Browse Nearby Words

femtometer
femtosecond
femur
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Cite this Entry

“Femtosecond.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/femtosecond. Accessed 28 Oct. 2026.

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