A concave mirror is a curved mirror in which the reflecting surface is bowed inward. This type of mirror is used to focus light waves. The concave mirror is also known as a converging mirror.
A convex mirror is a curved mirror in which the reflecting surface is bowed outward. This type of mirror is used to reflect light waves in a wide area. The convex mirror is also known as a diverging mirror.
The main difference between concave and convex mirror is that concave mirror converges light while convex mirror diverges light.