An Etymological Dictionary of Astronomy and Astrophysics

To allow to be done or occur.

Etymology (EN): From M.Fr. permetre, from L. permittere “give up, allow, allow to pass through,” from per- “through;” (from PIE base *per- “through, across, beyond;” cf. Gk. peri “around, about, beyond;” O.Pers. pariy “around, about,” Av. pairi “around, over;” Skt. pari; Indo-Iranian *pari- “around;” Mod.Pers. par-, pirâ- “around, about”) + mittere “let go, send.”

Etymology (PE): Parzâmidan, literally “to allow to go through,” infinitive of parzâm, from par- “through,” from O.Pers. pariy “around, about,” Av. pairi “around, over,” cognet with L. per-, as above

• zâm stem of Mid.Pers. zâmenidan “to let go, lead, send,”
  Mod.Pers. gâm “step, pace,” âmadan “to come;”
  O.Pers./Av. gam- “to come; to go,” Av. jamaiti “goes;” cf. Skt. gamati “goes;” Gk. bainein “to go, walk, step,” L. venire “to come;” Tocharian A käm- “to come;” O.H.G. queman “to come,” E. come; PIE base *gwem- “to go, come.”