A Pocket PC (P/PC, PPC) is also known by Microsoft as a 'Windows Mobile Classic device'. It is a hardware specification for a handheld-sized computer, personal digital assistant (PDA), that runs the Microsoft 'Windows Mobile Classic' operating system. It has some of the abilities of modern desktop PCs.

As of 2010, thousands of applications exist for handhelds adhering to the Microsoft Pocket PC specification, many of which are freeware. Some of these devices are also mobile phones. Microsoft-compliant Pocket PCs can be used with many add-ons such as GPS receivers, barcode readers, RFID readers, and cameras.

In 2007, with the advent of Windows Mobile 6, Microsoft dropped the name Pocket PC in favor of a new naming scheme. Devices without an integrated phone are called Windows Mobile Classic devices instead of Pocket PCs. Devices with an integrated phone and a touch screen are called Windows Mobile Professional devices and devices without a touch screen are called Windows Mobile Standard devices.

A pocket is a bag- or envelope-like receptacle either fastened to or inserted in an article of clothing to hold small items. Pockets may also be attached to luggage, backpacks, and similar items. In older usage, a pocket was a separate small bag or pouch.

In European clothing pockets began by being hung like purses from a belt, which could be concealed beneath a coat or jerkin and reached through a slit in the outer garment.

The word appears in Middle English as pocket, and is taken from a Norman diminutive of Old French poke, pouque, modern poche, cf. pouch. The form "poke" is now only used dialectically, or in such proverbial sayings as "a pig in a poke".

Historically, the term "pocket" referred to a pouch worn around the waist by women in the 17th to 19th centuries, mentioned in the rhyme Lucy Locket. Also called a hanging pocket.

"Pocket" is also a term for a sack in which hops were stored, generally with a capacity of 168–224 lb (76–102 kg).^{[citation needed]}

A watch pocket is a small pocket designed to hold a pocket watch, sometimes found in men's trousers and waistcoats and in traditional blue jeans. A besom pocket is a pocket cut into a garment instead of being sewn on. These pockets often have reinforced piping along the slit of the pocket, appearing perhaps as an extra piece of fabric or stitching. Besom pockets are found on a tuxedo jacket or trousers and may be accented with a flap or button closure. Camp pockets are pockets which have been sewn to the outside of the garment. They are usually squared off and are characterized by seaming.