Emily Dickinson Lexicon

PER, prep.

A Latin preposition, denoting through, passing, or over the whole extent, as in perambulo. Hence it is sometimes equivalent to very in English, as in peracutus, very sharp. As a prefix, in English, it retains these significations, and in chimistry it is used to denote very or fully, to the utmost extent, as in peroxyd, a substance oxydated to the utmost degree. Per is used also for by; as, per bearer, by the bearer.