What's an ewe neck?

(sorry if this is in the wrong spot)
I've been told that it's when a horse's neck is real hollow. But then today I overheard someone saying it's when a horse's neck is bulged? I'm confused..?

Thanks for the help in advance :]

A ewe necked horse is one with a neck that looks like that of a sheep or ewe after it has been shaved. This means it's very upright and over-muscled underneath.

Here's an example:

Hollow on the topline, bulging and overdeveloped on the underside.