from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun metrology An SI unit of time equal to 10−18 seconds.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun one quintillionth (10^-18) of a second; one thousandth of a femtosecond


from Wiktionary, Creative Commons Attribution/Share-Alike License

atto- +‎ second


Help support Wordnik (and make this page ad-free) by adopting the word attosecond.



Log in or sign up to get involved in the conversation. It's quick and easy.

  • one quintillionth of a second

    February 2, 2007

  • 0,000 000 000 000 000 001 of a second ("as")

    May 17, 2008

  • “Stress may be most readily associated with the attosecond pace of postindustrial society, but the body’s stress response is one of our oldest possessions.�?

    The New York Times, Brain Is a Co-Conspirator in a Vicious Stress Loop, by Natalie Angier, August 17, 2009

    August 21, 2009