per

¹

[ pur; unstressed per ]

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

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 O 5 ), permanganic (HMnO 4 ), persulfuric (H 2 S 2 O 8 ), acids; potassium permanganate (KMnO 4 ); potassium persulfate (K 2 S 2 O 8 ).

per.

³

abbreviation for

1. percentile.
2. period.
3. person.

Per.

⁴

abbreviation for

1. Persia.
2. Persian.

per

¹

/ pə; pɜː /

determiner

1. for every

   three pence per pound

preposition

1. (esp in some Latin phrases) by; through
2. as per
   according to

   as per specifications

3. as per usual informal.
   as usual

PER

²

abbreviation for

1. Professional Employment Register

per-

³

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

   perchlorate

   permanganate

8. not in technical usage a variant of peroxy-

   persulphuric acid

Usage Note

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.

Word History and Origins

Origin of per¹

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

Origin of per²

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

Word History and Origins

Origin of per¹

C15: from Latin: by, for each

Origin of per²

from Latin per through

Example Sentences

Added to drinking water at concentrations of around one part per million, fluoride ions stick to dental plaque.

From The Daily Beast

During an emergency that ratio could be allowed to drop to 8.5 people per orbit.

From The Daily Beast

Well over a thousand holes in, I average less than four strokes per hole.

From The Daily Beast

At least one child in CAR has been killed or gravely injured per day, and 10,000 have been recruited into militant groups.

From The Daily Beast

Bitcoin began 2013 with a roaring price of $770 per unit, and businesses right and left were converting to the ethereal product.

From The Daily Beast

I doubt that thirty persons per day are carried into or brought out of it by all public conveyances whatever.

From Project Gutenberg

The Act permits member banks to accept an amount of bills not exceeding 50 per cent.

From Project Gutenberg

At this period it brought enormous prices, the finest selling at from fifteen to eighteen shillings per pound.

From Project Gutenberg

In 1205 wheat was worth 12 pence per bushel, which was cheap, as there had been some years of famine previous thereto.

From Project Gutenberg

We did not talk much about the past at dinner, except—ah me, how bitterly we regretted our 10 per cent.

From Project Gutenberg