vIl is a verb meaning be ridgy. A raised ridge pattern is Su'nIm. There is a noun vIl, but it is unrelated and means hanger-on, something that is "just there."
Klingon has no articles a, an, or the. You can't say a * by putting a wa' in front of it. That means one ,* which is not the same thing.
So far as I know, we don't have a word meaning a single ridge.