Flip phone

A flip or clamshell phone consists of two or more sections that are connected by hinges, allowing the phone to flip open then fold closed in order to become more compact. When flipped open, the phone's screen and keyboard are available. When flipped shut, the phone becomes much smaller and more portable than when it is opened for use.

Motorola was once owner of a trademark for the term flip phone, but the term flip phone has become genericized and used more frequently than clamshell in colloquial speech. Motorola was the manufacturer of the famed StarTAC flip phone in the 1990s, as well as the RAZR in the mid-2000s. There were also flip "down" phones, like the Motorola MicroTAC series and was also widely used by Ericsson.

In 2010, Motorola introduced a different kind of flip phone with its Backflip smartphone. When closed, one side is the screen and the other is a physical QWERTY keyboard. The hinge is on a long edge of the phone instead of a short edge, and when flipped out the screen is above the keyboard.

Another unusual flip form was seen on the luxury Serene, a partnership between Samsung and Bang & Olufsen.

Clamshell came to be used as generic for this form factor. Flip phone referred to phones that opened on the vertical axis. As clamshells disappeared from the market, the terms again became disambiguated.

By the mid-2000s, "flip" designs reached the peak of their availability and declined afterwards, being replaced by sliders which in turn were completely replaced by slate smartphones.

See more at "Form factor of mobile phones".