Culinary definition of roast: Cooking, uncovered, in dry heat, in an electric, gas, or wood-fired oven. More-or-less exactly the same cooking process as baking, but roasting applies to meat, seafood, vegetables and fruit - never baked goods like bread, cake and pastry.
C@H FOOD FOR THOUGHT
One can roast in a pre-heated barbeque also. Caution is needed, but once mastered the result is perfection and there is no going back. If using a gas grill, first sear meat on primary grill, then move meat to the top shelf or a section of the grill that is not directly over a live burner - close the lid and roast (as you would in an oven, right) to finish.
On a charcoal barbeque, be sure to leave a patch of real estate free and clear of briquettes, then once the meat is seared on the hottest part of the grill, move it to an area of the grill directly overtop of the briquette-free zone. Close lid to finish roasting, but check and stir the hot coals on occasion if necessary, to maintain baking temperature.