WHAT THE HELL ARE COUPONS???

So, I see a financial headline from Reuters that says Fed adds permanent reserves by buying coupons. I decide I should read the article because I don't know what the hell they mean by "coupons." Obviously, they don't mean the kind of coupons I use to get my ground chuck for cheaper. So what do they mean by the word "coupons?" I don't know. I read the article and got nothing from it.

Here it is:

NEW YORK, Sept 9 (Reuters) - The Federal Reserve said on Thursday it was adding permanent reserves to the banking system by buying coupons.

The Fed said it was buying coupons maturing Aug. 15, 2007 to Dec. 15, 2008 for delivery on Friday.

The Fed excluded all callables, all Treasury Inflation Protected Securities (TIPS) and the 2-3/4 percent coupon maturing Aug. 15, 2007.

Earlier, the Fed added temporary reserves to the system through overnight system repurchase agreements and 14-day system repurchase agreements.

The fed funds rate last traded at 1.50 percent, the Fed's current target for the rate.

See? Nothing. No explanation, just an assumption that you actually know what the article is talking about.

Thanks, press! A simple definition is all I need.

Let the shrowd of mystery over the FR$ continue to obscure just how the hell it works!! YEAH!