• synonyms


  1. a combining form used in the names of units of measure equal to one quadrillion (1015) of a given base unit: petabyte.
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Origin of peta-

origin uncertain
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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British Dictionary definitions for peta


abbreviation for
  1. People for the Ethical Treatment of Animals
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  1. denoting 10 15petametres Symbol: P
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Word Origin

C20: so named because it is the SI prefix after tera-; on the model of penta-, the prefix after tetra-
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

Word Origin and History for peta


acronym for People for the Ethical Treatment of Animals; the group’s website says it was founded in 1980.

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Online Etymology Dictionary, © 2010 Douglas Harper

peta in Medicine


  1. One quadrillion (1015):petagram.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

peta in Science


  1. A prefix that means:
  2. One quadrillion (1015), as in petahertz, one quadrillion hertz.
  3. 250 (that is, 1,125,899,906,842,624), which is the power of two closest to a quadrillion, as in petabyte.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.