a. [mod.L. bīnālis twin, f. L. bīn-i two together, a pair: see -AL.] Twin, double, twofold.
1658. Ford, Witch Edmond., III. ii. Wks. (1811), 457. I have ’em already … Binal revenge, all this.
1806. W. Herschel, in Phil. Trans., XCVI. 227. Periodical binal revolution of stars about a common centre of gravity.
