supercell

1. (meteorology) A severe thunderstorm with updrafts and downdrafts that are in near balance, allowing the storm to maintain itself for several hours. Supercells often produce large hail, powerful downpours, very strong winds and sometimes tornadoes.Examples: "They watched the supercell that spawned the F5 killer that struck Oklahoma City spit out one tornado after another. In two cases, the researchers believe, the Dopplers captured tornadoes being formed — including the Oklahoma City monster."; "The storm system was a supercell, the kind that brew the deadliest tornadoes and most damaging hail in the United States, said Walker Ashley[…]"

2. (mineralogy) A repeating unit cell of a crystal that contains several primitive cells.