If you’ve used any kind of 3D program, this will be familiar to you already, but the tl;dr is Global space: Locked coordinate system, Local Space: movable coordinate system attached to any game object.
Here’s a local coordinate system for our player capsule. As you can see when I rotate around the y axis, the x and z axis turn along with the player gameObject. the coordinates are local to the gameobject.
When I change the axis to global, I can rotate the game object, but the x and z coordinates stay locked to the world coordinates. Global coordinates never change.
We can transform game objects with respect to local and world spaces, and as we’ll learn soon, they can have a huge effect on how we manipulate objects.