In general, an area that is totally or partially obscured from light by an object.

In Maya, an individual light source can produce no shadows (the default), depth map shadows or raytraced shadows. You can combine depth map shadow casting lights and raytraced shadow casting lights in a scene. Adjusting the attributes of depth map shadows or raytraced shadows can simulate shadows from many different types of real-world light sources and objects.

Depth map shadows and raytraced shadows produce similar results, though depth map shadows usually take less time to render. Generally, choose depth map shadows unless they cannot accomplish your visual goal.