Accuracy (ISO 1575) refers to a combination of trueness and precision. It encompasses both systematic error (trueness) and random error (precision). It should not be confused with Trueness.

A single result or entire set of results deviating in either trueness or precision from others in the set or from other sets, respectively, due to errors associated with measurement.

In exploration and mining rock and ore samples are tested (assayed) in Assay Laboratories. The word assay comes from the French word essai, which means "trial," an appropriate sense for a word that means to examine for analysis. As a noun, assay means a test or appraisal to determine the components of a substance or object. As a verb, it refers to the act of analyzing, or of conducting that test. It is usually used in chemistry-related fields like metallurgy and pharmaceuticals, but you can also assay a poem.

An old mining term still in common usage, synonymous with Reference Materials and Control Samples.