The Sony CLIÉ is a series of personal digital assistants (PDAs) running the operating system (OS) Palm OS, developed and marketed by Sony from 2000 to 2005. The devices introduced many new features to the PDA market, such as a jog dial interface, high-resolution displays, and Sony technologies like Memory Stick slots and ATRAC3 audio playback. Most models were designed and manufactured in Japan. The name was initially an attempt at a new coinage term, though it means tool in the Jèrriais language.

Palm OS was a mobile operating system initially developed by Palm, Inc., for personal digital assistants (PDAs) in 1996. Palm OS was designed for ease of use with a touchscreen-based graphical user interface. It was provided with a suite of basic applications for personal information management. Later versions of the OS were extended to support smartphones. The software appeared on the company's line of Palm devices while several other licensees have manufactured devices powered by Palm OS.