what is angle of deviation???pls tell me with correct naming of figues

The angle between the direction of the refracted ray and the direction of the incident ray when a ray of light passes from one medium to another.

The angle between the incident light ray and emergent light ray when it is passes through object such as prism or water drop.suppose in the case of  prism when light ray touches the surface of the prism it refracted and come out from the another side of the prism making some angle with intial light ray .this angle is called angle of minimudeviation of prism.