The area built into the sides of steep hills and mountains to grow crops is called a terraced field.

Here's why:

* Terraces: These are flat platforms cut into the slopes, creating a series of steps.

* Field: This refers to the land used for growing crops.

Terraced fields are a clever way to maximize usable land in mountainous regions. They help prevent soil erosion and allow farmers to cultivate crops in areas that would otherwise be too steep.