There are typically four stages in COPD, depending a bit on whether you subscribe to the GOLD staging or a variation. GOLD breaks it down roughly by FEV1, so 100-80% is stage one, or mild; 80-50% is stage 2 or moderate; 50-30% is stage 3 or severe and under 30 is sage four and very severe. GOLD also considers how many exacerbations and how active you are, but it's all pretty fuzzy, there are those who really don't fit and the lines get very blurry.

It sounds like a bunch of chap.