(Short: AABB)

An n-dimensional box that contains all of a given set of n-dimensional coordinates and is aligned to the coordinate system's axes (duh). This structure is used in 3D-graphics to perform collision detection. It is easier to create than an OBB, since the only data necessary are the minimum and maximum positions of all points along each axis. Also, intersection between AABBs are usually easier to detect than between OBBs since there's only one interval intersection test necessary per axis. The main downside is that AA bounds are bigger than or at least of equal size as their object aligned counterparts and thus AABB-trees usually need to be deeper than OBB-trees to attain a similar fit to the contained object.