1705 tr. G. Guillet de Saint-Georges i. at Mark A Horse Marks, that is, he shews his Age by a Black Spot call'd the Bud or Eye of a Bean [Fr. germe de féve], which appears about five and a half in the Cavity of the Corner-teeth, and is gone when the Horse is eight years old; then he ceases to mark, and we say, he has raz'd.
1736 N. Bailey et al. (ed. 2) Eye of a Bean, a black speck..in the cavity of the corner-teeth of a horse.
1798 T. Connelly & T. Higgins I. 7/3 A horse that marks still shewing the eye of the bean in his corner tooth.