Ambient light is any light a photographer or cinematographer did not bring to the shoot, either natural light or lighting found in a location.
Ambient Light: Definition, 6 Common Examples
How to Light for Darkness 5 Cinematography Techniques
What Is Ambient Light? Definition & Examples [With Tutorial]
What is Ambient Light & How to Use it in Photography
Photographic lighting - Wikipedia
OpenGL Light - Creating Light Sources in OpenGL, Light Types (ambient, diffuse, material color and specular highlight).
Types of Lighting in Film: Basic Techniques to Know - 42West
How to Light Your Photos and Videos Like an Expert
Ambient light goes functional
Understanding Shadow Colors (Ambient Light Part 2)
What is Ambient Light in Film and TV?