It's a multimedia multinetwork Pocket PC. Just like most Windows Mobile Professional devices.

It's not a smartphone which usually lack a keyboard and touchscreen, but at least offer some functional hardware keys (except for the iPhone).

I'd call the ones without true mobile networking (N770 etc.) PDAs rather than Tablets, I think a tablet shouldn't be able to fit in your pocket. Windows XP tablet edition already is 10 years old, so I don't really get the tablet craze recently.