Separate#

Reference

At some point, you will come to a time when you need to cut parts away from a mesh to be separate.

To separate an object, the vertices (or faces) must be selected and then separated, though there are several different ways to do this.

Selection: Separates the selected elements.
By Material: Separates fragments based on the materials assigned to the different faces.
By Loose Parts: Creates one object for every independent (disconnected) fragment of the original mesh.