Definition of per preposition from the Oxford Advanced Learner's Dictionary

per

preposition

pə(r)

pər

pɜː(r) strong form per pronunciation American

pɜːr

used to express the cost or amount of something for each person, number used, distance travelled, etc.Rooms cost £50 per person, per night.60 miles per hourThis country has a higher crime rate per 100000 of the population than most other European countries.

Idioms

as per something

following something that has been decided

The work was carried out as per instructions.

as per normal/usual

(informal) in the way that is normal or usual; as often happensEveryone blamed me as per usual.