How many types of shadows are there?

In the context of light and shadow, there are three main types of shadows: umbra, penumbra, and antumbra. The umbra is the darkest part of a shadow where all light is blocked, the penumbra is a partially shaded region surrounding the umbra, and the antumbra is the shadow's outermost region where the light source is only partially blocked. These distinctions are important in understanding the behavior of shadows in various lighting conditions.