Answer: The point at which light from objects within the radius of curvature will be focused.
A converging lens is a type of optical lens that is thicker at the center than at its edges (convex lens); this type of lens concentrate or converge (that is why its name) at a point the rays of light that pass through it.
This same procedure is done by a concave mirror as well.
In this context, focal point of both is where parallel rays of light from the object meet, or converge. Nevertheless, it is important to note the object must be within the radius of curvature of the lens or mirror.