saddle

1. A seat for a rider, usually made of leather, padded to span comfortably a horse's back, furnished with stirrups for the rider's feet to rest in, and fastened in place with a girth; also, a seat for the rider on a bicycle or tricycle.

2. A padded part of a harness which is worn on a horse's back, being fastened in place with a girth. It serves various purposes, as to keep the breeching in place, carry guides for the reins, etc.

3. A piece of meat containing a part of the backbone of an animal with the ribs on each side; as, a saddle of mutton, of venison, etc.

4. A block of wood, usually fastened to some spar, and shaped to receive the end of another spar.

5. <machinery> A part, as a flange, which is hollowed out to fit upon a convex surface and serve as a means of attachment or support.

6. <zoology> The clitellus of an earthworm.

7. The threshold of a door, when a separate piece from the floor or landing; so called because it spans and covers the joint between two floors.

<medicine> Saddle bar, any thin plicated bivalve shaell of the genera Placuna and Anomia; so called from its shape.

Synonym: saddle oyster.

Origin: OE. Sadel, AS. Sadol; akin to D. Zadel, G. Sattel, OHG. Satal, satul, Icel. Sothull, Dan. & Sw. Sadel; cf. Russ. Siedlo; all perh. Ultimately from the root of E. Sit.

Source: Websters Dictionary