Which term is used to describe the allowable variation in dimensions?

• A. Allowance
• B. Deviation
• C. Tolerance
• D. Modifier

Answer: (D)

The concept being tested is how we describe how much a manufactured dimension may vary from its intended size. That description is tolerance—the allowable range around the nominal dimension. For example, if a shaft is specified as 50.00 mm with a tolerance of +0.05 mm / -0.00 mm, any size from 50.00 to 50.05 mm is acceptable. This ensures parts will still fit and function together within the designed limits.

Allowance is the intentional difference between two mating parts to achieve a specific fit, not the general variation of a single part. Deviation refers to the actual difference from the nominal size, often describing what was produced rather than what is permitted. Modifier isn’t a term used for dimension variation in this context.