| 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). |

| peri- pref.
[Greek, from peri, around, near; see per1 in Indo-European roots.] |
peri- pref.
Around; about; enclosing: perimysium.
Near: perinatal.