A microhood is a microwave oven designed to be installed over a range as a range hood: it has lighting underneath and ventilation or air circulation.
The microwave-oven may include among its features a convection-oven.
A range-hood, often called a hood is installed over a range top to provide powered exhaust ventilation or, in cheaper models, air recirculation through a filter back into the room. Hoods almost always provide lighting.