1. Something which confines the legs or arms so as to prevent their free motion; specifically, a ring or band inclosing the ankle or wrist, and fastened to a similar shackle on the other leg or arm, or to something else, by a chain or a strap; a gyve; a fetter. His shackles empty left; himself escaped clean. (Spenser)
2. Hence, that which checks or prevents free action. His very will seems to be in bonds and shackles. (south)
3. A fetterlike band worn as an ornament. Most of the men and women . . . Had all earrings made of gold, and gold shackles about their legs and arms. (Dampier)
4. A link or loop, as in a chain, fitted with a movable bolt, so that the parts can be separated, or the loop removed; a clevis.
5. A link for connecting railroad cars; called also drawlink, draglink, etc.
6. The hinged and curved bar of a padlock, by which it is hung to the staple.
(Science: anatomy) Shackle joint, a joint formed by a bony ring passing through a hole in a bone, as at the bases of spines in some fishes.
Origin: OE. Schakkyll, schakle, AS. Scacul, sceacul, a shackle, fr. Scacan to shake; cf. D. Schakel a link of a chain, a mesh, Icel. Skokull the pole of a cart. See Shake.