1. a standard or criterion by which something is judged or measured
2. a dark stone formerly used to test the purity of gold and silver by the streak left on it when rubbed by the metal
Usage: historical

Examples

• The Constitution serves as a touchstone for American democracy.
• Her work became the touchstone for excellence in the field.
• The company uses customer satisfaction as its touchstone for success.
• This novel is considered a touchstone of modern literature.
• Ancient jewelers used a touchstone to verify the quality of precious metals.
• The teacher’s fairness was the touchstone by which students judged other instructors.