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

Origin of peta-

origin uncertain Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for peta

Contemporary Examples of peta

Historical Examples of peta

British Dictionary definitions for peta


abbreviation for

People for the Ethical Treatment of Animals



denoting 10 15petametres Symbol: P

Word Origin for peta-

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.

Online Etymology Dictionary, © 2010 Douglas Harper

peta in Medicine



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

peta in Science


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