From Latin per-
- In verbs: denoting the sense "through", as in perforate.
- In verbs: denoting the sense "thoroughly", as in perfect.
- In verbs: denoting the sense "to destruction", as in pervert.
- In adjectives and adverbs: denoting the sense "extremely", as in perfervid.
- chemistry Forming nouns and adjectives denoting the maximum proportion of one element in a compound, as in peroxide.Or A prefix added to the name of an element in a polyatomic ion denote the number of that element(usually four).
From Old French per (modern French par)
- Denoting the sense "by" or "per", as in perchance or perhaps.