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tolerance

TOL-er-uhnss /ˈtɒlərəns/

nounB2GRETOEFLIELTS

technicalprofessional

The allowable limit of variation in a physical dimension or value of a manufactured part without affecting its performance.

Tolerance is the margin of error specified by engineers, acknowledging that no factory can manufacture a part to an absolute, perfect size.

The story behind the word. From the Latin 'tolerantia' (enduring, bearing), from 'tolerare'. For centuries, it meant the ability to endure pain or accept differing opinions. In the mid-19th century, as mass production demanded interchangeable parts, engineers adopted the term to describe how much physical variation a machine could 'endure' before failing.

Word relationships

allowance: Allowance is an intentional difference in size between mating parts to achieve a specific fit, while tolerance is the unintentional variation allowed during manufacturing.
margin: Margin is a general term for safety or error, whereas tolerance is a highly specific, mathematically defined limit.

inaccuracy: Inaccuracy implies an uncontrolled error, whereas tolerance is a carefully planned and controlled limit of variation.

Commonly confused with

clearance: Clearance is the physical space intentionally left between two moving parts, while tolerance is the allowable variation in the size of those parts.

Word family

toleranced (adjective): Having specified dimensional tolerances.
tolerant (adjective): Able to endure specified conditions or variations.

Collocations

tight tolerance
dimensional tolerance
manufacturing tolerance
tolerance limits

Example sentences

"Because the gears must spin smoothly without wobbling, they require a very tight tolerance of plus or minus five microns." A quality control guide for a precision CNC machining factory.

Memory hook

Think of how much variation a machine can 'tolerate' or put up with before the parts jam or break. Tight tolerance means it tolerates very little error. Tolerance is the margin of error.

When not to use

Do not use to describe general patience or social acceptance on a design page; keep it strictly to the physical margin of error.

Fun facts

The concept of standardized manufacturing tolerances was popularized by Eli Whitney in the late 1700s when he demonstrated that muskets could be assembled from random, interchangeable parts.