Short for Personal Digital Assistant, PDA is a computer that fits in the palm of your hand to help collect such information as contacts, appointments, files, and programs. The picture is the Palm Tungsten | E2 and an example of a PDA. Because touchscreens were not available at the time to use a PDA a stylus was used to input data into the device. Also, with no Internet connection to backup or transfer data between a computer and the device it had to be connected to the computer, usually over the serial port.
The term PDA was first used by John Scully at CES on January 7, 1992 while describing the Apple Newton. Today, with the popularity and advances in smartphones, PDA's are rarely found and used as users migrate to smartphones like the iPhone.