\Coign\, n.
A var. spelling of {Coin}, {Quoin}, a corner, wedge; --
chiefly used in the phrase coign of vantage, a position
advantageous for action or observation.
      From some shielded nook or coign of vantage. --The
                                               Century.
      The lithosphere would be depressed on four faces; . . .
      the four projecting coigns would stand up as
      continents.                              --Nature.