An Etymological Dictionary of Astronomy and Astrophysics

A prefix meaning “about, around” (perimeter, periscope), “enclosing, surrounding” (pericardium), and “near” (perigee, perihelion).

Etymology (EN): From Gk. peri “around, about, beyond;” cognate with Pers. pirâ-, as below.

Etymology (PE): Pirâ-, variant par- “around, about,” from Mid.Pers. pêrâ; O.Pers. pariy “around, about,” Av. pairi “around, over,” per- “to pass over, beyond;”
cf. Skt. pari; Indo-Iranian *pari- “around;” PIE base *per- “through, across, beyond;” cf. Gk. peri “around, about,
beyond;” L. per “through.”