Pocket computer

A pocket computer is a class of handheld computer characterized by very short displays (typically accommodating only one or a handful of lines of text) and calculator-style alphanumeric keypads. Pocket computers occupy a small footprint, allowing the unit to be comfortably stashed in one's pocket when on the go, and usually weigh less than 1 pound (0.45 kg). Many feature a port for an expansion chassis, allowing the computers to be used with external peripherals.

Pocket computers had their peak of popularity in the early 1980s, but sales quickly plateaued and declined in Western markets as consumers became aware of their limitations. In Japan, where they were invented, pocket computers maintained their popularity and continued to be used as teaching aids into the 21st century.