What is the difference between 'diameter' and 'distance' in tolerancing?

• A. Distance is a circular dimension used for round holes.
• B. Diameter and distance are identical terms within tolerancing.
• C. Diameter applies to circular features; distance is a linear measurement not necessarily related to a circle.
• D. They are interchangeable in tolerancing.

Answer: (C)

In tolerancing, diameter is a dimension that defines the size of a circular feature, measured across the circle through its center. Distance, on the other hand, is a linear measurement of separation between two features (or between a feature and a datum) along a straight line, and it isn’t inherently tied to a circle. So the size of a circular hole is described with a diameter, while the spacing or location between features is described with a distance. That’s why this option is correct: diameter applies to circular features; distance is a linear measurement not necessarily related to a circle.