The vortex is where the air spins around a line which is usually located in the center. The use of wind or a strong air flow is needed in order for the vortex to continue its pattern. Vortexes can be commonly seen in tornadoes. However, they can also be seen in waves and smoke rings. When the water in a whirlpool swirls around, the water is moving in one direction around a common point in the center.
There are different types of vortices. The rotational vortices is when the flow is continued by an outside force in order for it to continue. In a tornado, there must be pressure to continue its vortex. The pressure is more dynamic when it is near the center.