The Collaborative International Dictionary of English v.0.48:
Gemel \Gem"el\, n.
1. One of the twins. [Obs.] --Wyclif.
2. (Heb.) One of the barrulets placed parallel and closed to
each other. Cf. Bars gemel, under Gemel, a.
Two gemels silver between two griffins passant.
Gemel hinge (Locksmithing), a hinge consisting of an eye or
loop and a hook.
Gemel ring, a ring with two or more links; a gimbal. See
Gemel window, a window with two bays.