3D Rigging is the process of creating a skeleton for a 3D model so it can move. Most commonly, characters are rigged before they are animated because if a character model doesn't have a rig, they can't be deformed and moved around. Rigging is setting up a skeleton that moves the mesh. It would be mind-bogglingly tedious to move every single vertex if you wanted to make a character move. Instead, we create a skeleton, complete with bones, and then move the bones in order to move the character. The skeleton is called an Armature. An Armature is composed of many Bones. Each Bone can have some vertices assigned to it. When you move a Bone, just the vertices assigned to it will move, and all the other vertices will stay still. The goal is to set up the Bones in the Armature so that neighboring Bones move neighboring vertices smoothly and naturally.