Technically, whether the covered pot is in the oven or on the stove, as long as the cut of roast is braised and then simmered in a closed pot, it is a pot roast.

pot roast
Pot roast is a braised beef dish. Pot roast is typically made by browning a roast-sized piece of beef (taken from a tougher cut) to induce a Maillard reaction, then slow-cooking in an acidulated liquid in a covered dish.
Food & Nutrition Dictionary and Research Guide

braised
adjective
cooked by browning in fat and then simmering in a closed container