Longman Dictionary of Contemporary English - per

~ prep 1 for each  (per kilo/gallon/metre etc (=for each kilo etc))  (Apples are 60 cents per pound.)  (My car does about 12 miles per litre (=for each litre of petrol) .) per head (=for or by each person)  (How much food should we allow per head? ) 2 per hour/day/week etc during each hour etc  (How many calls do you make per day? ) [m]miles/kilometres per hour (=used for measuring speed)  (a train travelling at 150 miles per hour) 3 according to  (as per sth)  (work carried out as per your instructions) 4 as per usual spoken used when something annoying happens which has often happened before  (Hardy was late, as per usual.)  (- see also per annum, per capita)