(tôr-nāʹdō) noun. 1. A rotating column of air usually accompanied by a funnel-shaped downward extension of a cumulonimbus cloud and having a vortex several hundred yards in diameter whirling destructively at speeds of up to 500 miles (800 kilometers) per hour. 2. A violent thunderstorm in western Africa or nearby Atlantic waters. 3. A whirlwind or hurricane, tornado, puting beliung.