1)The center of a circle which passes through a curve at a given point and has the same tangent and curvature at that point.
2)The point in the center of the sphere from which the mirror was sliced is known as thecenter of curvature 

Hope i helped u
Pls mark my answer as the best
thanks for yur answer but I want it according to concave and convex mirrors
In geometry, the center of curvature of a curve is found at a point that is at a distance from the curve equal to the radius of curvature lying on the normal vector.
this is the centre of curvature