A mirror that is flat completely reflects light; however, if a mirror is curved, the light will reflect in a certain direction, depending on whether it is concave (curved in) or convex (curved out).
Both convex and concave mirrors are essentially bent mirrors similar to the curve of a ball.
Concave mirrors are bent inward as if you are looking at the inside of a ball. Convex mirrors are bent outward as if you are looking at the outside of a ball.
Convex mirrors reflect light outward and concave mirrors reflect light inward.
Both types of these mirrors are employed in a variety of practical ways such as security mirrors, passenger-side car mirrors and within telescopes and cameras.
Convex mirrors make images appear smaller, while concave mirrors make images appear larger.