(in O. Eng. storm, and so in Du. and Low Ger.; in O. H. Ger. and mod. Ger. Sturm; the root is probably that seen in "stir," to rouse, move, disturb, cf. Ger. stiiren), a disturbance of the atmosphere, accompanied by high winds or by heavy falls of rain, hail or snow, together with thunder and lightning. The word is not a part of scientific terminology, such terms as "area of low pressure" and "cyclone" being used. In the Beaufort scale the wind-force of a storm is estimated at Io-II and the limit of velocity at from 56 to 75 m. per hour. (See METEOROLOGY, and for magnetic storms MAGNETISM, TERRESTRIAL.)