The sides of a stage are called **the wings**. This is because they are typically located on either side of the main performance area, just like the wings of a bird extend from its body. The wings provide space for performers, props, and equipment to be concealed and stored until they are needed on stage. They also serve as entrances and exits for actors during a performance, allowing them to make their entrances and exits discreetly. In summary, the wings of a stage are the areas on either side of the main stage where performers and equipment are organized and concealed before and during a performance.