a prefix meaning “about” or “around” (perimeter, periscope), “enclosing” or “surrounding” (pericardium), and “near” (perigee, perihelion), appearing in loanwords from Greek (peripeteia); on this model, used in the formation of compound words (perimorph).
Origin of peri-
< Greek, prefixal use of perí (adv. and preposition)
1777, from Persian pari, from Avestan pairika. Race of superhuman female beings originally represented as malevolent, later as angelic genii (cf. sense evolution of English fairy, to which it is not related).
word-forming element meaning "around, about, enclosing," from Greek peri (prep.) "around, about, beyond," cognate with Sanskrit pari "around, about, through," Latin per, from PIE *per- (1) "forward, through" (see per).