Spaghetti, and macaroni, and ravioli, and... well, you could go on for quite a long time listing pasta shapes, but they are all distinct things. If someone says "spaghetti" I am going to assume they mean one specific thing.

Asian "noodles" and Italian "noodles" are all noodles. Ramen is arguably closer to spaghetti than it is to udon, and they certainly aren't soba, etc.