Ambient, or general,light is illumination that fills an entire room. Its source is sometimes an overhead fixture, but the light itself does not appear to come from any specific direction. the key to good ambient lighting is making it inconspicuous. It is merely the backdrop for the rest of the room, and it changes with the surrounding environment always providing light out never becoming obvious.
For example, ambient lighting used during the day should blend in with the amount of natural light entering the room. At night, you should be able to adjust the level of supplemental artificial light so that it doesn't contrast jarringly against the darkness outside.
pictures Helpful Suggestions For Ambient Lighting In Your Home.