touchstone.

1. A reference used to judge quality, authenticity, or adequacy.

2. A dark stone used to test precious metals by the mark they leave.

Use it for

Words that belong together

• ethical touchstone
• touchstone of quality

On the page

Participant safety remained the touchstone of the review.

Usage notes

Primary category: analysis / argumentation / evidence. Forms: Singular touchstone; plural touchstones. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Writing functions: argumentation, evidence, inference. Commonness: moderately common.