While the word "virtual" is typically overused in the computer world, it is aptly placed in the phrase "virtual reality." According to the American Heritage Dictionary, virtual means "existing or resulting in essence or effect though not in actual fact, form, or name." It can also mean "created, simulated, or carried on by means of a computer or computer network." Therefore, virtual reality is best described as an illusion of reality created by a computer system.
A person may enter a world of virtual reality by putting on special glasses and headphones attached to a computer system running the virtual reality program. These devices immerse the user with the sights and sounds of the virtual world. Some virtual reality systems allow the user to also wear gloves with electronic sensors that can be used to touch or move virtual objects. As the user moves his head or hands, the computer moves the virtual world accordingly in real-time.
Virtual reality has been widely used for entertainment purposes, but the technology has found its way into the military and medical fields as well. While virtual reality systems have advanced significantly over the past decade, for the most part they are still more "virtual" than reality.