Example 5

On the top four strings, we have what could be called an Asus2 chord. But by adding the C# (major 3rd) on the fifth string, we take it out of the ‘sus’ category, giving us Aadd9/C#. Going further to add the open sixth string (E), we relieve the C# of its responsibility as bass note, relegating it to major 3rd (at the lower end of the action). The logical name for this seems to be Aadd9/E!