See Figure 1
Camber is the inward or outward tilting of the front wheels from the vertical. When the wheels tilt outward at the top, the camber is said to be positive (+). When the wheels tilt inward at the top, the camber is said to be negative (-). The amount of tilt is measured in degrees from the vertical and this measurement is called the camber angle.
Caster is the tilting of the front steering axis either forward or backward from the vertical. A backward tilt is said to be positive (+) and a forward tilt is said to be negative (-).
Toe is the turning in of the front wheels. The actual amount of toe-in or toe-out is normally only a fraction of a degree. The purpose of toe is to ensure parallel rolling of the front wheels. Excessive toe-in or toe-out will cause tire wear.