The definition of the Fujita scale is a scale for measuring the wind speed of a tornado and its potential for destruction with F0 meaning wind speeds of 40-72 mph up to F6 which is wind speeds up to 319 to 380 mph.
An example of the Fujita scale is what a tornado expert would use to determine the damage a tornado could do if it sets down on a town.
A numerical scale for measuring the wind speed and corresponding destructive power of a tornado: replaced (2007) by theEnhanced Fujita Scale.
Origin of fujita-scale
From the Japanese-American meteorologist Tetsuya Theodore "Ted" Fujita (藤田哲也).