Ambient light, in the context of computer graphics, 3D rendering, and lighting simulation, refers to the overall environmental illumination that comes from all directions. It is a type of indirect light that fills the scene and helps to create a base level of brightness, reducing harsh shadows and providing a sense of global illumination.
Ambient lighting in 3D rendering is a technique used to simulate indirect light that contributes to the overall illumination of a scene. It helps create a sense of global illumination and provides a baseline level of brightness to all surfaces in the environment. Ambient lighting is especially useful for filling in shadows and creating a more evenly lit scene. Here is how it looks with ambient light tuned to maximum intensity.
And with ambient light disabled
In the right-side inspector panel under the scene section there is an ambient light section. By default the ambient light is present on the 3D scene in a white color.