The TerrainThe landscape in your scene. A Terrain GameObject adds a large flat plane to your scene and you can use the Terrain’s Inspector window to create a detailed landscape. More info
See in Glossary system uses Unity engine resources to function correctly. Unity includes these resources in your Player build when you have at least one Terrain instance in a SceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
See in Glossary that is part of the build. If you only create Terrain dynamically at runtime, make sure you include a Terrain component somewhere in your build as a placeholder. You can disable that Terrain instance (uncheck the box next to the Terrain name in the Inspector window), and put it in a Scene that your game or app doesn’t load.