noun pl. tornadoes -·does or tornados -·dos

1. ☆ a violently whirling column of air, with wind speeds of about 100 to 300 miles per hour, extending downward from a cumulonimbus cloud, esp. in Australia and the central U.S.: usually appearing as a rapidly rotating, slender, funnel-shaped cloud and typically causing great destruction along its narrow path
2. in W Africa and the adjacent Atlantic, a severe thundersquall
3. any whirlwind or hurricane

Etymology: altered (prob. based on Sp tornar, to turn) < Sp tronada, thunder, thunderstorm < tronar, to thunder < L tonare, to thunder