The term roast comes from the original spit-roasting that was done over open fires. Today, it is a term used for dry heat cooking usually done in an oven; this applies to both meat and poultry. This sort of dry heat cooking is usually called baking when talking about cakes and pastries and some vegetables. Of course, when I was a youngster, we always had the baked dinner, but the term seems to have generally changed to roast. Cooking uncovered is essential when roasting as covering would create steam, and you want to get that lovely browning effect. You will find that most ovens have little hot spots, and that the back of the oven is hottest, so make sure you rotate your dish during cooking to help ensure an even cooking, or place the largest or thickest part of the roast to the back.