per

¹ American  

[pur, per] / pɜr, pər /

preposition

1. for each; for every.

   Membership costs ten dollars per year. This cloth is two dollars per yard.

2. by means of; by; through.

   I am sending the recipe per messenger.

3. Also according to; in accordance with.

   I delivered the box per your instructions.

   He managed to monopolize the meeting, per usual.

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adverb

1. Informal. each; for each one.

   The charge for window-washing was five dollars per.

per- ² American  

1. a prefix meaning “through,” “thoroughly,” “utterly,” “very”: pervert; pervade; perfect.

2. 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 (H 2 C 2 O5 ), permanganic (HMnO4 ), persulfuric (H 2 S 2 O8 ), acids; potassium permanganate (KMnO4 ); potassium persulfate (K 2 S 2 O8 ).

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per. ³ American  

abbreviation

1. percentile.

2. period.

3. person.

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Per. ⁴ American  

abbreviation

1. Persia.

2. Persian.

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per- ¹ British  

prefix

1. through

   pervade

2. throughout

   perennial

3. away, beyond

   perfidy

4. completely, throughly

   perplex

5. (intensifier)

   perfervid

6. indicating that a chemical compound contains a high proportion of a specified element

   peroxide

   perchloride

7. indicating that a chemical element is in a higher than usual state of oxidation

   permanganate

   perchlorate

8. (not in technical usage) a variant of peroxy-

   persulphuric acid

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per ² British  

/ pə, pɜː /

determiner

1. for every

   three pence per pound

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preposition

1. (esp in some Latin phrases) by; through

2. according to

   as per specifications

3. informal as usual

PER ³ British  

abbreviation

1. Professional Employment Register

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Usage

Per meaning 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.

Etymology

Origin of per¹

First recorded in 1580–90; from Latin: “through, by, for, for each”; for

Origin of per-²

From Latin, combining form of per, and used as an intensive; per

Example Sentences

Us said that in December 2025, the court revised the former couple’s agreement to $1,206 per month in child support, with $43,401.96 due for unpaid past support.

From Los Angeles Times • Apr. 3, 2026

He doesn’t describe it as a buyer’s market, per se, but he noted that buyers are getting some power back after it was in the hands of sellers for years.

From MarketWatch • Apr. 3, 2026

Some monitors there recorded levels of PM2.5 -- particles small enough to enter the bloodstream and linked to diseases like cancer -- of over 900 micrograms per cubic metre.

From Barron's • Apr. 3, 2026

Harvard’s faculty will vote on a proposal to cap A’s per course, which now comprise over 50% of undergraduate grades.

From The Wall Street Journal • Apr. 3, 2026

Convoys drove through the night, at a maximum speed of twenty miles per hour, toward the missile sites.

From "Fallout: Spies, Superbombs, and the Ultimate Cold War Showdown" by Steve Sheinkin