Synecdoche+Vs.+Metonymy

What is the difference between metonymy and synecdoche ?

I don't know if this will help but I found it and thought it was slightly entertaining (:

**Synecdoche vs. Metonymy** OK, so you're collecting body parts from your victims. The question is, why are you collecting them? Say you had a piano teacher who terrorized you as a child. Maybe she locked you inside the piano for hours, until you were deaf in one ear from the horrible clanging of the little felt-covered hammers. So you decide to kill women piano teachers, and to keep a little lacquer box full of their index fingers. Is that synecdoche, because the index finger stands for the whole piano teacher? Or is it metonymy, because you're keeping the fingers of women who remind you of your old teacher? I dunno. OK, look at it this way. If you're gathering body parts because of their external symbolism—like the famous Memphis Ear-Snatcher, who only killed people whose left ears reminded him of the snails he loved with a doomed passion—then that's definitely metonymy. But if you take a piece of every fashion designer, because //Project Runway// traumatized you, then that's synecdoche. I think. The main thing is, don't collect body parts for no good reason, because that's just dumb. I have to confess something. During my mutilation phase, I had to have a toe from everyone I killed. Why? I don't know. I figured I would know what to do with them when I had enough of them. It's actually kind of embarrassing, but one day I just sat down with this pile of toes and suddenly felt like the world's biggest asshole. I mean, what are you going to do with a dozen toes? Make a toe menorah or something? I don't know. They weren't even the same kind of toe, or one of each. I was keeping them frozen, so they had a dusting of freezer burn on them, and they looked sort of like off-season strawberries. I realized there was no great art project waiting to come out of these toes. It was just the wrong medium or something. I ended up having to go out to the backyard and bury them all, and then of course my dog dug them all up a week later. I felt like such a dork reburying all those toes. (http://www.mcsweeneys.net/2006/3/24anders.html).


 * Synecdoche: using a part to refer to a whole.**

Examples: -new set of wheels. -lend a helping hand. -all hands on deck. -get your butt over here.


 * Metonymy: an object representing an idea or concept.**

Examples: -an author's name, instead of his or her work (e.g., I am reading __Stephen King__ right now!) -crown being royalty. -living by 'the book' -the pen is mightier than the sword. -the big apple representing New York City