at·​to·​sec·​ond ˈa-(ˌ)tō-ˌse-kənd How to pronounce attosecond (audio)
: one quintillionth (10−18) of a second
An attosecond is to a second what a second is to the age of the universe.IEEE Spectrum

Examples of attosecond in a Sentence

Recent Examples on the Web Electrons move and their energies shift at the miniscule timescale of attoseconds. Will Sullivan, Smithsonian Magazine, 4 Oct. 2023 At the atomic level, the motions of electrons and nuclei typically take place over the course of attoseconds. Daniel Garisto, Scientific American, 3 Oct. 2023 At the heart of this technique is attosecond x-ray absorption spectroscopy, which allowed the ICFO research team to study how electrons behave on timescales as short as a billionth of a billionth of a second (an attosecond) when exposed to powerful infrared radiation. IEEE Spectrum, 9 Jan. 2024 The shortest pulses produced today are only a few dozen attoseconds long. Will Sullivan, Smithsonian Magazine, 4 Oct. 2023 One attosecond is one-quintillionth of a second, or 0.000000000000000001 seconds. Charlie Wood, Quanta Magazine, 3 Oct. 2023 The number of attoseconds in a single second is the same as the number of all the seconds that have elapsed since the universe burst into existence 13.8 billion years ago, according to the Royal Swedish Academy of Sciences, which awards the Nobel Prizes. Katrina Miller, New York Times, 3 Oct. 2023 For many years light pulses were stuck in the femtosecond regime (one femtosecond is 1000 attoseconds). Daniel Garisto, Scientific American, 3 Oct. 2023 Enlarge / An attosecond is to one second as one second is to the age of the universe. Jennifer Ouellette, Ars Technica, 3 Oct. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'attosecond.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


atto- + second entry 4

First Known Use

1962, in the meaning defined above

Time Traveler
The first known use of attosecond was in 1962

Dictionary Entries Near attosecond

Cite this Entry

“Attosecond.” Dictionary, Merriam-Webster, Accessed 19 Apr. 2024.

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