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atto-

combining form at·to- \ˈa-(ˌ)tō\

Definition of atto-

  1. :  one quintillionth (10−18) part of <attogram>



Origin and Etymology of atto-

International Scientific Vocabulary, from Dan or Norwegian atten eighteen, from Old Norse āttjān; akin to Old English eahtatīene eighteen


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of or relating to the heavens

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