[pur; unstressed per]


for each; for every: Membership costs ten dollars per year. This cloth is two dollars per yard.
by means of; by; through: I am sending the recipe per messenger.
according to; in accordance with: I delivered the box per your instructions.


Informal. each; for each one: The charge for window-washing was five dollars per.

Origin of per

1580–90; < Latin: through, by, for, for each. See for
Can be confusedper purr (see usage note at the current entry)

Usage note

Per for a or an or for each occurs chiefly in technical or statistical contexts: miles per gallon; work-hours per week; feet per second; gallons of beer per person per year. It is also common in sports commentary: He averaged 16 points per quarter. Per is sometimes criticized in business writing in the sense “according to” and is rare in literary writing.


a prefix meaning “through,” “thoroughly,” “utterly,” “very”: pervert; pervade; perfect.
Chemistry. 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), permanganic (HMnO4), persulfuric (H2S2O8), acids; potassium permanganate (KMnO4); potassium persulfate (K2S2O8).

Origin of per-

< Latin, combining form of per per, and used as an intensive


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

Related Words for per

by, through, apiece, each, for, to, via

Examples from the Web for per

Contemporary Examples of per

Historical Examples of per

British Dictionary definitions for per



for everythree pence per pound


(esp in some Latin phrases) by; through
as per according toas per specifications
as per usual informal as usual

Word Origin for per

C15: from Latin: by, for each


abbreviation for (in Britain)

Professional Employment Register



away, beyondperfidy
completely, throughlyperplex
indicating that a chemical compound contains a high proportion of a specified elementperoxide; perchloride
indicating that a chemical element is in a higher than usual state of oxidationpermanganate; perchlorate
(not in technical usage) a variant of peroxy- persulphuric acid

Word Origin for per-

from Latin per through
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 per

1580s (earlier in various Latin and French phrases), from Latin per "through, during, by means of, on account of, as in," from PIE root *per- (1) "Base of prepositions and preverbs with the basic meanings of 'forward,' 'through,' and a wide range of extended senses such as 'in front of,' 'before,' 'early,' 'first,' 'chief,' 'toward,' 'against,' 'near,' 'at,' 'around'" [Watkins]. Cf. Sanskrit pari- "around, about, through," pura "before, formerly;" Avestan pairi- "around," paro "before;" Old Persian pariy; Hittite para- "on, forth;" Greek peri "around, about, near, beyond," paros "before," para "from beside, beyond," pro "before;" Latin pro "before, for, on behalf of, instead of," porro "forward," prae "before;" Old English fore (prep.) "before, in front of;" (adv.) "before, previously;" German vor "for;" Old Church Slavonic pra-dedu "great-grandfather;" Russian pere- "through;" Lithuanian per "through;" Old Irish air- Gothic fair-, German ver-, Old English fer-, intensive prefixes.


word-forming element meaning "through, throughout; thoroughly; entirely, utterly," from Latin preposition per (see per (prep.)).

Online Etymology Dictionary, © 2010 Douglas Harper

per in Medicine



Thoroughly; completely; intensely:perfuse.
Containing an element in its highest oxidation state:perchloric acid.
Containing a large or the largest possible proportion of an element:peroxide.
Containing the peroxy group:peracid.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.