A phablet is a mobile device combining or straddling the size formats of smartphones and tablets. The word is a portmanteau of phone and tablet. The term is largely obsolete by the late 2010s, since average smartphone sizes eventually morphed into small tablet sizes, up to 6.9 inches (180 mm), with wider aspect ratios.

A mobile device or handheld computer is a computer small enough to hold and operate in the hand. Mobile devices are typically battery-powered and possess a flat-panel display and one or more built-in input devices, such as a touchscreen or keypad. Modern mobile devices often place emphasis on wireless networking, to both the Internet and to other devices in their vicinity, such as headsets or in-car entertainment systems, via Wi-Fi, Bluetooth, cellular networks, or near-field communication.