What is PDA?

PDA: 

PDA means Personal Digital Assistant. PDAs are used for sorting and retrieving information. Like most computer devices, many PDA can connect to the Internet. PDAs extremely compact. They have many built in features such as calculator, clock and calendar. PDAs can be used for sending and receiving mail, browsing the web, video calling, word processing,
scanning bar codes, accessing
GPS, playing games and so on.