touchstone
გამოთქმა:
/ˈtʌtʃstəʊn/
არსებითი სახელი
Universal
a piece of fine-grained dark schist or jasper formerly used for testing alloys of gold by observing the colour of the mark which they made on it. a standard or criterion by which something is judged or recognized:they tend to regard grammar as the touchstone of all language performance