World space
The shared coordinate system in which every object in a scene is placed relative to the others.
A model is authored in its own local space, usually with the origin between its feet. The model matrix – position, rotation and scale – moves it out into world space, where it can collide with other things and be lit by the same lights. From there the camera's view matrix takes over, and the chain ends in normalized device coordinates and finally pixels.
Mixing up the spaces is one of game programming's most loyal sources of bugs: apply a force in local space and the car lurches sideways instead of forwards. In a scene graph the transforms nest, so a child's world position is its parent's transform times its own. Huge open worlds run into precision trouble far from the origin, which is what a floating origin exists to fix.