Here's why:
* The concept of theme parks existed long before Disney World: Amusement parks with rides, shows, and attractions existed in various forms throughout history. For example, the first roller coaster was built in Russia in 1817, and early amusement parks like Coney Island in the late 1800s were quite popular.
* Disneyland was the first Disney theme park: While Disney World is a massive entertainment complex, Disneyland in Anaheim, California was the first theme park built by Walt Disney in 1955.
Disney World, opened in 1971, was built on the foundation laid by Disneyland, taking the concept of themed areas and immersive experiences to a larger scale. But the concept of theme parks existed well before either of them.