Psion is a British technology company known for its development of portable computing devices in the 1990s. It gained popularity for its Psion Series 3 and Psion Series 5 personal digital assistants (PDAs), which featured a unique clamshell design and a robust operating system. These devices were widely used for business applications and personal organization. The company also created the EPOC operating system, which later evolved into Symbian OS, a platform that powered many smartphones in the early 2000s. Psion's innovations contributed significantly to the evolution of mobile computing and influenced the design of modern handheld devices.