Doc:Glossary/Bounding Box
Bounding Box
Determines the geometric centers and axes for all objects, including those of complex shape (joined objects, boolean unions, etc). All Blender objects may be seen as representative bounding boxes by selecting Bounding Box drawing mode in the Viewport Shading combo box on the 3D Viewport header bar --- hotkey Z toggles bounding box and solid drawing modes. Bounding boxes can only be viewed in Object Mode.