D defs.my
Entry 1 sense Webster, 1913

Per

/pẽr/ · IPA /pɜː/
01 prep. Through; by means of; through the agency of; by; for; for each; as, per annum; per capita, by heads, or according to individuals; per curia…
  1. 1.
    Through; by means of; through the agency of; by; for; for each; as, per annum; per capita, by heads, or according to individuals; per curiam, by the court; per se, by itself, of itself. Per is also sometimes used with English words.
Phrases & compounds
Per annum — by the year; in each successive year; annually.
per cent — by the hundred; in the hundred; a proportion multiplied by one hundred; -- used esp. of proportions of ingredients, rate or amount of interest, and the like; most commonly used in the shortened form, per cent, or as one word, percent; as, 5 is ten per cent of 50. It is commonly symbolized with the per cent sign, “%”.
Per diem — by the day.