A storm is a kind of severe weather marked by hard wind (a wind storm), thunder and lightning (a thunderstorm), heavy precipitation such as ice (ice storm), or wind transporting some substance through the atmosphere (as in a dust storm, snowstorm, etc).
A strict meteorological definition of a storm is a wind measuring 10 or higher on the Beaufort scale, meaning a wind speed of 89 kilometers per hour (55 miles per hour) or more; however, popular usage is not so restrictive.
See also