noun
withers
WITH-erz/ˈwɪðərz/
The ridge between a horse's shoulder blades.
The saddle rests just behind the withers on the horse's back.

Etymology
The name probably combines “against” with a plural ending. It is usually explained as naming the part of the animal that opposes the load, connecting the shoulder ridge with resistance to a burden.
In context
The males are between 22 and 25 inches at the withers, and the females are a little shorter,
So they really do accommodate horses with higher withers.
More examples
- We measure the pony's height at the withers.
- She brushes dried mud from the horse's withers.
- A poorly fitted saddle can rub against the withers.
Forms
withers