Westworld serves as the setting for the film's protagonists, Peter Martin and John Blane, and antagonist, The Gunslinger. While its counterparts, Medieval World and Roman World, involve both side stories and have a place in the main narrative, Westworld, as the name implies, is the focal point of the first movie.
Two years later in the timeline of the sequel, Futureworld, Westworld had become Delos' scapegoat for the park's earlier problems. This allows the covering up of identical problems in Medieval and Roman World, allowing them to reopen without the public's fear. As such, Westworld was left deserted during the events of Futureworld. It was replaced with Spa World and Futureworld.
During the hovercraft approach to the park, the in "flight" preview film calls Westworld "Western World". The film continues to describe Westworld as
"Western World is a complete re-creation of the American frontier of 1880. Here it is possible to relive the excitement and stresses of pioneer life to the fullest. Western World is a life of lawless violence, a society of guns and action."Later, Delos' unnamed scientists describe the park's breakdowns as starting in Roman World and eventually spreading to become a rise in "Western World breakdowns."