Shear in geology is when rocks move past each other, like how your hands can slide past each other when you rub them together. When rocks move past each other, they can create different shapes and formations, like folds or faults.
Think of it like playing with Play-Doh. If you push two different colors of Play-Doh together and then move one hand in a different direction, you can create different patterns and shapes in the Play-Doh. This is kind of like what shear does to rocks.
Shear can happen because of different forces, like pressure from the earth's crust or from tectonic plates moving past each other.
So, in simple terms, shear is when rocks move past each other and create different shapes and patterns, just like when you play with Play-Doh.