| PERI | flagellate with a thick test composed of plates |
|---|---|
| PERI | marine and freshwater dinoflagellates |
| PERI | type genus of the family Peridiniidae |
| PERI | outer layer of the spore-bearing organ in many fungi |
| PERI | a pale green variety of chrysolite |
| PERI | a dark coarse-grained igneous rock consisting principally of olivine |
| PERI | periapsis in Earth orbit |
| PERI | an angle of 360 degrees |
| PERI | periapsis in solar orbit |
| PERI | periapsis in orbit around Jupiter |
| PERI | a venture undertaken without regard to possible loss or injury |
| PERI | a source of danger |