■ noun
1》 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.
2》 a standard or criterion.
■ noun
1》 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.
2》 a standard or criterion.
Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004