mesocyclone

[ mez-uh-sahy-klohn, mes-, mee-zuh-, -suh- ]
/ ˌmɛz əˈsaɪ kloʊn, ˌmɛs-, ˌmi zə-, -sə- /

noun Meteorology.

a small cyclone that arises near a thunderstorm and is sometimes associated with the occurrence of tornadoes.

Origin of mesocyclone

First recorded in 1970–75; meso- + cyclone