If Disney World is the largest theme park what do you call parks that are in it?

Disney World isn't a single theme park, but a resort complex made up of multiple theme parks, water parks, hotels, and other entertainment options.

Here's how you would refer to the parks within Disney World:

* Theme Parks: You would call them theme parks or specifically Disney theme parks to distinguish them from other parks. Examples: Magic Kingdom, Epcot, Hollywood Studios, Animal Kingdom.

* Water Parks: You would call them water parks. Examples: Blizzard Beach, Typhoon Lagoon.

So, while Disney World is a resort complex, the individual parks within it are still theme parks and water parks.