Per-

Part of speech: noun (n.)

1. A prefix used to signify through, throughout, by, for, or as an intensive as perhaps, by hap or chance; perennial, that lasts throughout the year; perforce, through or by force; perfoliate, perforate; perspicuous, evident throughout or very evident; perplex, literally, to entangle very much.

2. Originally, denoting that the element to the name of which it is prefixed in the respective compounds exercised its highest valence; now, only that the element has a higher valence than in other similar compounds; thus, barium peroxide is the highest oxide of barium; while nitrogen and manganese peroxides, so-called, are not the highest oxides of those elements.

Part of speech: preposition (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 curiam, by the court; per se, by itself, of itself. Per is also sometimes used with English words. Per annum, by the year; in each successive year; annually. -- Per cent, Per centum, by the hundred; in the hundred; -- used esp. of proportions of ingredients, rate or amount of interest, and the like; commonly used in the shortened form per cent. -- Per diem, by the day. [For other phrases from the Latin, see Quotations, Phrases, etc., from Foreign Languages, in the Supplement.]