Question

what is reflection of light by curved surface

Answer 1

when the ray of light returns by the second optical medium to the first optical medium with a change in angle is called reflection of light

Answer 2

hay!!
Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. 

Curved Mirrors - A curved mirror is a mirror with a curved reflective surface, which may be either convex (bulging outward) or concave (bulging inward). Most curved mirrors have surfaces that are shaped like part of a sphere.