The figure below is the labelled diagram

Incident ray: The ray of light that is incident on a surface

Refracted ray: When a light ray passes through a second medium and changes its direction, it is called a refracted ray.

Emergent ray: It is the light ray that is leaving a surface after reflection or refraction.

Angle of refraction: It is the angle (w.r.t to the normal at the surface) by which the incident ray is deviated at the second medium.

Angle of deviation: It is the angle between the incident ray and the emergent ray.

Angle of emergence: It is the angle of the light coming out of the medium