Definition of touchstone
1 : a black siliceous stone related to flint and formerly used to test the purity of gold and silver by the streak left on the stone when rubbed by the metal
2 : a test or criterion for determining the quality or genuineness of a thing
3 : a fundamental or quintessential part or feature : basis <a touchstone film of that decade> <now considered a touchstone of the city's life — Michael Specter>
Examples of touchstone in a sentence
Good service is one touchstone of a first-class restaurant.
<his book has long been a touchstone for travel writing that aspires to be literature>
Did You Know?
Our example sentence uses "touchstone" in its most recently acquired sense: "a fundamental part." The earlier sense, "a criterion for quality" (as in "I Love Lucy is often seen as a touchstone for comparison with today's TV comedy shows"), provides a better clue to the original meaning of "touchstone," however. The "criterion" sense, which goes back more than 470 years, alludes to a method of testing the purity of a sample of gold. The sample was rubbed on a piece of dark quartz or jasper - the "touchstone." The mark it made was compared to adjacent rubbings on the touchstone from gold of known purity. This method has proved accurate enough that touchstones are still used by jewelers today.
First Known Use of touchstone
Synonym Discussion of touchstone
TOUCHSTONE Defined for English Language Learners
Definition of touchstone for English Language Learners
: something that is used to make judgments about the quality of other things
Seen and Heard
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