Word of the Day : April 21, 2021

touchstone \TUTCH-stohn\ noun

Definition

1 : a fundamental or quintessential part or feature : basis

2 : a test or criterion for determining the quality or genuineness of a thing

3 : a black siliceous stone related to flint and used to test the purity of gold and formerly silver by the streak left on the stone when rubbed by the metal

Did You Know?

Since the early 16th century, touchstone has referred to a particular kind of siliceous stone (that is, stone containing silica) used to do a particular job: determine the purity of precious metals. The process involves comparing marks made by rubbing a sample of a metal of known purity to marks made by a metal of unknown purity. The method is accurate enough in the case of determining the purity of gold that it is still in use today. Figurative use extended from this literal use, with touchstone functioning as a word for a test or criterion to determine the quality of a thing, and later to refer to a fundamental or quintessential part or feature of something.

Aired April 21, 2021

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