HARNESS Copy link • HARNESS 1. Armor, Vid: Of a horse, helcium (ἕλκιον, probably “collar,” Apul., Met., 9, p. 222, 30, and p. 227, 23): habenae (reins). 2. v. Arm, Vid: To put on harness. To harness a horse, perhaps *equum instruere; if for draught, jumentis jugum imponere.