Which term describes a surface, hole, or edge that is used as a datum?

A datum feature is a specific term used in engineering and manufacturing, particularly in the context of geometric dimensioning and tolerancing (GD&T). It refers to a physical feature, such as a surface, hole, or edge, that serves as a reference point for the measurement and assembly of a part. The significance of selecting a datum feature lies in its ability to provide a consistent base for orientation and positional accuracy in the design and manufacturing processes.

When a surface is designated as a datum feature, it allows for precise referencing when determining relationships between different features on the part. Using a datum feature ensures that parts can be accurately assembled and inspected, which is crucial for maintaining the intended functionality and fit of the final product.

The other terms, while they may seem similar, do not carry the same specific meaning in the context of print reading and manufacturing tolerances. For example, a reference point may imply a general location but does not necessarily denote the structural or functional aspect required from a datum feature. An anchor point typically relates to securing an object rather than serving as a geometric reference, while a control feature may refer to various aspects of quality control without the precise implications of measurement that a datum feature holds.