tornado
Definitions
A mobile, destructive vortex of violently rotating winds having the appearance of a funnel-shaped cloud and advancing beneath a large storm system.
A localized, violently destructive windstorm occurring over land, especially in the US Midwest, and characterized by a funnel-shaped cloud extending toward the ground.
Examples
The small town was devastated when a powerful tornado touched down in the middle of the night.
We watched the dark clouds swirl in the distance, fearing that a tornado might be forming.