As I recall, "Spaghetti Western" was something of a derogatory term to indicate an Italian in the director's chair, or that it was shot in Italy. I could be wrong though, and if someone else knows for certain, I hope they pipe up.

Kind of amusing, if you think about it. Only Westerns got this appellation. You never heard about "Spaghetti Horror" or "Spaghetti Romance". :D