You pronounce it: [si-nek-duh-kee] (I know that second part looks like a bad word–at first glance, see I know what you are thinking!)
1) a figure of speech in which a part is used for the whole or the whole for a part, the special for the general or the general for the special, as in ten sail for ten ships or a Croesus for a rich man.
I heard it in class discussion when this guy said,
Zadie Smith [in White Teeth] is using synecdoche for this paragraph.
I was like, “what?” Sadly, I wasn’t familiar with the term. I hurried home to look it up.