The Workspace window is the main window for displaying and manipulating model. the grid, the coordinate axis, and bounding boxes are displayed on the workspace window. ( See View  >> Bounding Box / Axis / Grid )

A bounding box is the smallest box that encloses all the given faces.  There are two kinds of bounding box; shell bounding box and group bounding box. A shell / group bounding box includes the maximum and minimum point of the shell / group on the basis of the global coordinate system.