A saddle is a leather seat that you put on the back of an animal so that you can ride the animal.

If you saddle a horse, you put a saddle on it so that you can ride it.

A saddle is a seat on a bicycle or motorcycle.

A saddle of lamb, rabbit, or venison is a piece of meat taken from the middle of the animal's back.

If you saddle someone with a problem or with a responsibility, you put them in a position where they have to deal with it.

If you are in the saddle, you are riding a horse.

If you are in the saddle, you are in power or in control of a situation.