| plethodon | (n) type genus of the Plethodontidae, Syn. genus Plethodon |
| plethodontidae | (n) small mostly terrestrial New World salamanders having neither lungs nor gills as adults, Syn. family Plethodontidae |
| eastern red-backed salamander | (n) common salamander of eastern North America, Syn. Plethodon cinereus |
| lungless salamander | (n) mostly terrestrial salamanders that breathe through their thin moist skin; lay eggs in moist places on land; rarely enter water, Syn. plethodont |
| western red-backed salamander | (n) salamander of the Pacific coast of North America, Syn. Plethodon vehiculum |