[ tɔ:'neɪdəʊ ]
■ noun ( plural ~es or ~s ) a mobile, destructive vortex of violently rotating winds having the appearance of a funnel-shaped cloud.
Derivatives
tornadic -'nadɪk adjective
Origin
C16: perh. an alt. of Sp. tronada 'thunderstorm', by assoc. with Sp. tornar 'to turn'.