Definify.com
Webster 1913 Edition
Per-
Per-
.[See
Per
.] 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.
(Chem.)
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.