Light is described by its quality and direction.
Direct (or hard) light-the light strikes the subject from one angle and creates sharp shadows as in sunlight.
Diffused light-the light hits the subject from many angles and creates soft shadows as in cloudy weather.
Front light: Light and camera aiming towards the subject from same position, few shadows.
Side light: Light is at 90 degrees to the camera/subject axis.
Backlight: Light is on the opposite side of the camera from the subject.