/pə(r); pɚ; strong form 强读式 pɜ:(r); pɝ/
prep (used to express rates, prices, etc 用以表示比率、价格等) for each (unit of time, length, etc) 每, 每一（时间、长度等单位）:
60 per day 每天60英镑 *
2 per person 每人2英镑
* calculated per square yard 以每平方码计算的 *
45 revolutions per minute 每分钟45转 *
100 miles per hour 每小时100英里

prep
[Date: 1300-1400; Language: Latin;Origin:'through, by']
per hour/day/week etc
during each hour etc
　The park attracts 4 million visitors per year.
miles/kilometres per hour
(=used for measuring speed)
　a speed limit of 40 miles per hour
for each
　How much does it cost per kilo?
　rooms costing £40 per night
　Admission is £9.95 per adult.
　My car does 12 miles per litre (=for each litre of petrol) .
　The meal cost $25 per head (=for or by each person) .
as per sth
formal according to something
　The work was carried out as per your instructions.
as per usual/normal
spoken used when something annoying happens which has often happened before
　Jenny was late, as per usual.
→per annum, per capita