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.

Light. Read This if You Want to Take Great Photographs by Henry Carroll