Wi-Fi Protected Access
The English used in this article may not be easy for everybody to understand. (February 2012)
Wi-Fi Protected Access (also known as WPA and WPA2) is the name for a number of standards to use encryption on a Wireless LAN. The standards were created because researchers had found several weaknesses in Wired Equivalent Privacy. Wired Equivalent Privacy, or WEP was the standard that came before it.
Products that have the label WPA were designed to work with most cards, even those that came out before there was WPA. This is not true for access points though.
Products with the WPA2 implement all of the standard. This started in 2004 and is more secure, but it may not work with some older hardware.