I have an extensive background in linguistics and taught it before. At no time was there ever a "compound" in English in which they were two words. Compounds are single words, not phrases. The whole concept of "compounding" is merging two words together as one. By definition, "a compound is a lexeme", and lexemes do not have spaces in the middle of them. An item with a space is a "phrase". 2. As I proved above, it does not. 3. Many sources say otherwise. There was a whole section devoted to listed references. Look under "Scope" and you can see where it lists references provided.