1. Pocket PC (pocket personal computer) is a generic label that is sometimes used to describe a mobile device that provides many of the same functions as a desktop computer. Informally, the term is used as a synonym for smart phone or personal digital assistant (PDA). The term is considered by many industry experts to be outdated.
2. Pocket PC is a a hardware specification from Microsoft for a small, handheld computing device that uses the Microsoft's Windows Mobile operating system. Microsoft refers to the pocket PC that runs the Microsoft Windows Mobile Classic operating system as a Windows Mobile Classic device.