Base Circle: this is the smallest circle tangent to the cam profile.
Trace Point: this is theoretical point on the follower whose motion explained the movement of the follower.
Pitch Curve: If cam is fixed & follower is taken around the cam, the curve traced through the trace point is known as the pitch curve.
Pressure Angle: This is the angle among the direction of the follower movement & normal to the pitch curve at a specific point.
Pitch Point: This is a point on the pitch curve where pressure angle is maximum.
Prime Circle: This is the circle of minimum radius that may be drawn tangential to pitch curve.
Displacement Diagram: This is a graph plotted among displacement of the follower & cam angle.