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(word root) through, very
Examples of words with the root per-: pervert, pervade, perfect
Abused, Confused, & Misused Words by Mary Embree Copyright © 2007, 2013 by Mary Embree


1. Thoroughly; completely; intensely: perfervid.
2. Containing an element in its highest oxidation state: perchloric acid.
3. Containing a large or the largest possible proportion of an element: peroxide.
4. Containing the peroxy group: peracid.

[Latin, from per, through; see per in Indo-European roots.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. through: pervade.
2. throughout: perennial.
3. away, beyond: perfidy.
4. completely, throughly: perplex.
5. (intensifier): perfervid.
6. (Elements & Compounds) indicating that a chemical compound contains a high proportion of a specified element: peroxide; perchloride.
7. (Elements & Compounds) indicating that a chemical element is in a higher than usual state of oxidation: permanganate; perchlorate.
8. (Elements & Compounds) (not in technical usage) a variant of peroxy-: persulphuric acid.
[from Latin per through]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(pɜr; unstressed pər)

1. for or in each or every; a or an: Membership costs $10 per year.
2. according to; in accordance with: I delivered the box per your instructions.
3. by means of; by; through: Send it per messenger.
4. Informal. each; for each one: The charge was five dollars per.
as per, according to; in accordance with: arranged as per instructions.
[1580–90; < Latin: through, by, for, for each. See for]
usage: per meaning “for each” occurs chiefly in technical or statistical contexts: miles per gallon; cost per person. It is also common in sports commentary: 16 points per quarter.A or an is often considered more suitable in nontechnical use. per or as per meaning “according to” is sometimes criticized and is rare in edited writing.


1. a prefix meaning “through,” “thoroughly,” “utterly,” “very”: pervert; pervade; perfect.
2. a prefix used in the names of inorganic acids and their salts that possess the maximum amount of the element specified in the base word: percarbonic (H2C2O5) acid; potassium permanganate (KMnO4).
[< Latin, prefixal use of per per]


1. Persia.
2. Persian.


1. percentile.
2. period.
3. person.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.