Source : Webster's Revised Unabridged Dictionary (1913)

Peri- \Per"i-\ [Gr. ?, prep.]
   A prefix used to signify around, by, near, over, beyond, or
   to give an intensive sense; as, perimeter, the measure
   around; perigee, point near the earth; periergy, work beyond
   what is needed; perispherical, quite spherical.