I like this question asking "What is a noun-modifying clause?", but I cannot decide (probably due to my lack of knowledge of linguistics) if this is a simple definition question, or a question that should be moved to the linguistics SE.
It has the potential to be moved, because what a noun modifying clause is is something that would be present across languages.
It could stay right here because it's asking for a definition of an English phrase.
Should it be here or there?