Vortex or Vortices (plural)

A vortex is the spiraling motion of air or liquid around a center of rotation with closed streamlines. The shape of media or mass rotating rapidly around a center, forms a vortex. It is a flow involving rotation about an axis (not always oriented vertically though; sometimes possessing a horizontal axis).

A vortex can be any circular or rotary flow that possesses vorticity .    Vorticity is a mathematical concept used in fluid dynamics. It can be related to the amount of "circulation" or "rotation" in a fluid.