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 lithosphere would be depressed on four faces; . . . the four projecting coigns would stand up as continents.
© Webster 1913