Rep Power: 187

So my friend and I were looking at the exhaust on my 2006 Civic.
He is familiar with older car models and so we didn't recognize some of the things on my exhaust.
Specifically a round thing that looks like a muffler, but it comes before the muffler

The thing in question is directly above the part labeled #2 in this diagram, the part itself is not labeled in the diagram...

I have no clue what I'm looking at, so figured I'd ask and see if any of you guys know what it is.

(If any of you have a similar diagram with actual labels that'd be great)

 
Rep Power: 280

It looks like you are looking at the mid pipe.

 
Rep Power: 518

We generally call it a resonator, or mid-muffler.

 
Rep Power: 512

x2 on the resonator.