Open Mike:

Nether= lower. In this case The Netherlands is The Low Countries.
This explains the hill in Amersfoort known as "De Berg" (The Mountain). This can be cycled up in a minute, but for them, that is a mountain.

"nether regions" is often used for the "below the belt" areas of the body in polite company.

"The netherworld" is used for Hell in the same way that "Underworld" would be used


Cheers

Nigel