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.

---

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 ).

---

per. ³ American  

abbreviation

1. percentile.

2. period.

3. person.

---

Per. ⁴ American  

abbreviation

1. Persia.

2. Persian.

---

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

---

per ² British  

/ pə, pɜː /

determiner

1. for every

   three pence per pound

---

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

---

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 American Heart Association recommends limiting sodium intake to no more than 2,300 mg per day, with an ideal target of less than 1,500 mg for most adults, especially those with high blood pressure.

From Science Daily

Even reducing intake by 1,000 mg per day can lead to meaningful improvements in blood pressure and overall heart health.

From Science Daily

Russia is in the midst of a demographic crisis, with fertility rates at 1.4 children per woman, far below the 2.1 threshold that demographers say is needed to keep the population at its current level.

From Barron's

Front-month West Texas Intermediate crude oil futures rose 1.2% to $102.60 per barrel, and front-month Brent crude oil futures gained 1.2% to $105.18 a barrel, ICE data showed.

From The Wall Street Journal

The cost of gasoline hit an unwelcome benchmark in the Los Angeles area on Tuesday as the average price per gallon officially reached the $6 mark, according to the American Automobile Assn.

From Los Angeles Times