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

The number of births per 1,000 women ages 15 to 44—the general fertility rate—reached a record low of 53.1 in 2025, according to provisional data from the Centers for Disease Control and Prevention.

From The Wall Street Journal • Apr. 9, 2026

Front-month WTI crude oil futures are 2.8% higher at $97.03 per barrel; front-month Brent crude oil futures are 2.5% higher at $97.14 a barrel.

From The Wall Street Journal • Apr. 9, 2026

In normal times, more than 100 ships move through the waterway per day, taking oil, natural gas, fertilizer, and other cargoes from the Middle East to Asia and Europe.

From Barron's • Apr. 8, 2026

It was trading at over $60 per share in 2021.

From Los Angeles Times • Apr. 8, 2026

Large earthquakes, which had been coming at the rate of one an hour in late March, went down to one per day by April 11.

From "Mountain of Fire" by Rebecca E. F. Barone