Definitions for "SUPERCELL"
The largest thunderstorms that approach a steady-state internal structure for a few hours and are able to produce large hail and tornados. The NWS defines supercells as thunderstorms that have a persistent, rotating updraft as part of their structure - these rotating updrafts have the potential to spawn deadly tornados.
a large, rotating severe thunderstorm
a large thunderstorm whose updrafts and downdrafts are