Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

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


Learn More about atto-


Seen and Heard

What made you want to look up atto-? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

a simplified speech bridging languages

Get Word of the Day daily email!