Scenario

To view all the scenarios in all games, see The Complete Scenario List

A scenario is a preset park that may or may not have guests, rides or scenery. The player is confronted by objectives, and sometimes a time limit in which to complete them.

In RollerCoaster Tycoon
There are a total of 21 scenarios in RCT1. At the beginning of the game, only 6(unsure?) scenarios are available. As scenarios are completed more are unlocked. The scenarios for the most part get progressively harder to complete. The Loopy Landscapes and Corkscrew Follies expansion packs add... (need more info)

In RollerCoaster Tycoon 3
In Roller Coaster Tycoon 3, each scenario had 3 difficulty levels; Apprentice (the easiest), Entrepeneur (middle) and Tycoon (hardest). Each one was denoted by a hat. Apprentice was a bronze cap, entrepeneur was a silver bowler hat and tycoon was a gold top hat.