Below are definitions of important tornado terms.

• dry line: the boundary where winds from the Gulf of Mexico and Canada meet and clash
• eye: the calm, cloudless center of a hurricane around which the storm winds whirl
• funnel: the spinning cloud that reaches down to earth from the storm
• mesocyclone: the column of storm winds stretching upward and downward through the storm clouds, and from which the tornado funnels drop
• satellite tornadoes: smaller tornadoes that spin off from major tornadoes and may go their own way
• SKYWARN: ESSA’s (now NOAA’s) network of volunteer tornado spotters
• supercells: the storm clouds that give birth to mesocyclones and their tornadoes
• tornado: a powerful column of winds spiraling around a center of low atmospheric pressure
• tornado warning: issued when twisters have actually been seen or detected by radar; intended as a warning for people to evacuate
• tornado watch: indicates that tornadoes may occur in the next several hours in a specific area
• TOTO: a device dropped in the path of a tornado to measure its strength, speed, and direction
• waterspout: a tornado occurring over the sea; a twisting, spiraling funnel over the water

Forces of Nature: ThinkQuest 2000 (Team #C003603)

http://library.thinkquest.org/C003603/english/tornadoes/glossary.shtml