A rotating column of whirling wind over land, usually accompanied by a funnel shaped downward extension of calumnious cloud and having a vortex several hundred yards in diameter whistling destructively at speeds of upto 300 miles per hour, usually very violent and destructive in a narrow path, often for miles
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UK: A storm of wind of extreme violence. It originates in a funnel-shaped cloud that rotates. The barometric pressure may drop so severely and rapidly that buildings may actually explode from within.