Define a tolerance and list three possible sources

Tolerance is the permissible limit or limits of variation in a physical dimension, a measured value or physical property of a material, manufactured object, system, or service. Three posible sources can be a measured value (temperature for example, a physical distance or a propierty like the compression of a metal.

Dimensions, properties, or conditions may have some variation without significantly affecting functioning but a variation beyond the tolerance is said to be noncompliant, rejected, or exceeding the tolerance.

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