What is a bend in a layer of rock called?

A bend in a layer of a rock is known as a fold, which is caused by compression that leads to rocks either bending or breaking. Folds that produce a type of upward arch are known as an anticline, according to Education.com.

Stress that acts on the rock layers can cause deformation. The result of past in-and-out and up-and-down movement in layers of rocks is not very often clear when viewed from the surface. This is because the evidence on the surface has worn away over the years. The deformed layers or underlying patterns become evident when sections have been cut away. This happens when roadways are made.