A wok is a pan used primarily for Asian-style cooking. It has rounded or straight sloping sides which makes it easier to toss and move food that is cooked at high heat.
Some woks have one long handle while others have two smaller handles. Woks can be used directly over heat. Heavy duty ones having a rounded bottoms fit in special burners or over braziers. For home stoves they may come with a base so that the bottom of the pan can sit upright for gas stoves. For electric stoves, though, the bottom is flat.
Electric woks have rounded bottoms, but are heated throughout the bottom. Woks may or may not have an adaptable rack for draining fried foods. The rack can also be used for steaming, too.
Below are two examples of woks. The left is one used in professional kitchens – it just drops in over the fire. The one on the right has a flat bottom that can be used on a flat range.