atto-

a combining form that enters into compounds denoting a unit one-quintillionth (10−18) the size of the unit named by the stem.

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Origin of atto-

< Danish or Norwegian att(en) eighteen + -o-

Words nearby atto-

attius, attleboro, attlee, attn, attn., atto-, attolaser, attophysics, attorn, attorney, attorney general
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for atto-

atto-

prefix

denoting 10 –18attotesla Symbol: a

Word Origin for atto-

from Norwegian, Danish atten eighteen
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for atto-

atto-

pref.

One quintillionth (10-18):attometer.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.