PER, 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 of 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.

PER annum, [Latin] by the year; in each year successively.

PER se, [Latin] by himself; by itself; by themselves.