A group (role) is used to combine a set of logically related elements. The group (role) should be used to group similar elements while the region (role) or landmark (role) is used to group the portions of the page. Group (role) is used to relate the similar items of a tree widget, limit to list items in a HTML list etc. Group (role) relates the child elements which are siblings. Row (role), rowgroup (role) are similar types of ARIA roles which form a logical relation in a grid or table widgets.