Combination of Orientation and Form:
Parallelism is very common in its surface form. When dealing with any flat surfaces, flatness may be called out, but parallelism is usually more critical, since the relation of surfaces in an assembly is more important.
Max Material Condition with Axis:
Straightness, Axis Angularity, Axis Parallelism and Axis Perpendicularity can all be called out and controlled with a gauge in maximum material condition. However only perpendicularity and straightness are used commonly. Please see our page on Maximum Material Condition for more information.