Dictionary.net

Rider\'s seat placed on back of horse &c. (usu. concave-shaped of leather with side-flaps& girths& stirrups) or forming part of bicycle &c. or of some agricultural machines (PACK, SIDE, -s.; in the s., mounted, fig. in office or control; put s. on right, wrong, horse, blame right, wrong, person); part of shaft-horse\'s harness that bears shafts; s.-shaped thing, e.g. ridge between two summits, support for cable or wire on top of suspension-bridge pier or telegraph-pole, joint of mutton or venison consisting of the two loins; saddleback, (Arch.) tower roof with two opposite gables, saddlebacked hill, kinds of bird (esp. the Grey Crow) & fish, (adj.) saddlebacked; saddlebacked, with upper outline concave, (Arch.) having saddleback; s.-bag, one of pair of bags laid across horse behind s., kind of carpeting (in imitation of Eastern s.-bb. of camels) used in upholstering chairs &c.; s.- boiler, of concave form used in heating-apparatus; s.-bow, arched front of s. [BOW]; s.-cloth, laid on horse\'s back under s.; saddlefast, firmly seated in s.; s.-horse, for riding; s.-pin, by which bicycle &c. s. fits into socket; s.-tree, frame of s., also N.-Amer. tulip-tree (with s.-shaped leaves); hence saddleless a. (Vb) put s. on (horse &c.); burden (person) with task, responsibility, &c.; put (burden) (up)on (person). [old English]