Definitions:
a seat fastened on the back of a horse or other animal for riding, typically made of leather and raised at the front and rear.

a low part of a ridge between two higher points or peaks

a shaped support on which a cable, wire, or pipe rests.

the lower part of the back in a mammal or fowl, especially when distinct in shape or marking

put a saddle on (a horse)

burden (someone) with an onerous responsibility or task