An Etymological Dictionary of Astronomy and Astrophysics

A mass of rotating air with high wind speeds at its center. It is produced in a very severe thunderstorm and appears as a funnel cloud extending from the base of a Cumulonimbus to the ground.

Etymology (EN): Tornado, metathesis from Sp tronada “thunderstorm,” from tronar “to thunder,” from L. tonare “to thunder,” → thunder.

Etymology (PE): Pic-tuf, from pic present stem of picidan “to twist, entwine, coil” (Mid.Pers. pecidan “to twist, entwine”) + tuf short for tufân, → storm.
Tufân-e picandé, from tufân→ storm + picandé agant noun/adj. of picidan</i “to twist, roll.”