What does the word touchstone mean?

Usage examples for touchstone

  1. The 'sense of chastity' is the touchstone of conjugal fitness, and is bestowed in this wise: When the Divine breaths have so pervaded the nervous structures that the higher attributes of sensation begin to waken from their immemorial torpor, and to react against disease, a sixth sense is as evident as hearing is to the ear, or sight to vision. – History of American Socialisms by John Humphrey Noyes
  2. The woman took the thimble and examined it, weighed it, and submitted its metal to the test of the touchstone. – Autobiography of a Pocket-Hankerchief by James Fenimore Cooper
  3. This explains not only why they lack the depth of tone seen in the complete medallions below them, but also why they were so deceptive until this touchstone of comparison was applied. – Stained Glass Tours in France by Charles Hitchcock Sherrill