For instance, right now I'm just getting my feet wet with a new short story. I've decided it's going to be about the Mafia, and I know there is a lot of terminology that I want to use to spice it up. However, how is everyone going to know that my reference to "Uncle Sugar" is the FBI?

For the most part, I'll hope people will be able to figure out my words from their context, yet it is still nagging me.

So, should I just use those words that people can determine out of context, and leave out any words I doubt people could work out... or should I write it using whatever terminology I decide to and include a list of the terminology with my manuscript? I know that many publications in magazines(what I plan on writing for) will include definitions on the page, but how would I go about that when I submit my manuscript?

Anyway, I'm usually a bit off when I try to explain things, but hopefully you get the general gist of what I'm getting at.
 

Harry scowled at Marcus. "You wanna explain to me why Uncle Sugar came pokin' 'round the shop today?" The FBI had just left, and any minute longer, and he knew that they would have found the body.

I don't know... Hope that helps.

I'm a firm believer in jargon IN SO FAR as I believe that characters should be true to life, true to themselves. But if I can't figure out from the context, I won't flip to the back to read a glossary but I will likely put the book back on the boostore shelf and not read it any more.
 

Why not read some William Gibson. He's not doing mafia stuff, but he is the king of jargon. Look at how he handles it.

Mary
 

Michael Crichton is famous for working jargon into his stories, too. But the way he spoon feeds it to the reader doesn't appeal to me.