Answer:
A tornado is just one kind of vortex. Vorticies (vortexes) can come in a variety of shapes and sizes and can form in just about any liquid or gas that isn't too viscous.
Tornadoes are vorticies of air that range in size from a few yards to about 2.5 miles in diameter and a few thousand feet to a few miles in height. They produce violent winds capable of causing damage. Some tornadoes have smaller vorticies circling within them. Tornadoes are driven by complicated interactions of air currents within a thunderstorm.
Other vorticies form in a variety of mediums, though on earth the most common are in air and water. They range from tiny eddies a fraction of an inch in size to weather systems and ocean currents thousands of miles across. No other type of vortex on earth can match the intensity of the most violent tornadoes, though the storms on other planets (which are usually enormous vorticies) can.