The bend in rock that forms where part of the crust is compressed is called a fold.

Here's a breakdown:

* Compression: When tectonic plates collide, the rock layers in the Earth's crust are squeezed together.

* Folding: Due to the compression, the rock layers bend and warp, creating folds.

There are different types of folds, including:

* Anticlines: U-shaped folds where the oldest rock layers are in the center.

* Synclines: Downward-facing, U-shaped folds where the youngest rock layers are in the center.

* Monoclines: One-sided bends in rock layers.

Folding is a common geological process that contributes to the formation of mountains and other landforms.