Pronunciation: (pûr; unstressed pur),[key] —prep. 1. for each; for every: Membership costs ten dollars per year. This cloth is two dollars per yard. 2. by means of; by; through: I am sending the recipe per messenger. 3. according to; in accordance with: I delivered the box per your instructions.
—adv. Informal.each; for each one: The charge for window-washing was five dollars per.
1. a prefix meaning “through,” “thoroughly,” “utterly,” “very”: pervert; pervade; perfect. 2. Chem.a prefix used in the names of inorganic acids and their salts that possess the maximum amount of the element specified in the base word: percarbonic (H2C2O5), permanganic (HMnO4), persulfuric (H2S2O8), acids; potassium permanganate (KMnO4); potassium persulfate (K2S2O8).