The Coriolis force is caused because the Earth rotates at a different linear velocity in the Equator compared to that in the North and South poles. This force makes objects that are not fixed to the ground move in different directions. For example, the hurricanes in the Northern Hemisphere spin counterclockwise and when travelling some distance they move to the right. While in the Southern Hemisphere they spin clockwise and move to the left. The effect of the Corioli force is extremely important on Earth because it determines the water and air currents, for example. Therefore, it is not an insignificant force.
Thought, it is an apparent force because it is not a force directly applied to the air and water, but a force produced by the side effect of the rotation of the Earth.
We can observe the "Coriolis Force" in a system that experiences a rotational movement, when a body is in motion with respect to said system, which is taken as a reference parameter. The "effect" consists on a relative acceleration experienced by the body in the rotating system.
The Coriolis Force is named "apparent force" or "effect", because it is not a real force, since there is nothing to produce it. Coriolis Force is produced in the studied body because the observation system is rotating.
