The smartphone is literally a "smart phone". It is a mobile device that combines mobile phone functions (calls and SMS) with those for managing personal data.
The smartphone is a small pocket computer equipped with a touch display, external and internal camera, Internet connection and GPS connectivity. Today, all tech companies produce smartphones, and some have made them their flagship product, like Apple with the iPhone.
The smartphone can derive from the evolution of a PDA to which are added functions (not always all) of a telephone (for this reason also called PDA-Phones) or vice versa, of a mobile phone to which PDA functions are added.
The most interesting feature of smartphones is the ability to install additional applications (Apps), which add new features.