An oven is a small space or a chamber that is able to keep the heat inside. Due to this, the temperature inside the chamber is very high. The source of heat can be electricity, gas, firewood. Ovens are used not only for baking and cooking but a potter also puts his clay pots into a "bhatti" so that the pots gets fired at a high temperature.
All types of breads (pav, sliced bread) are made in an oven.