IEEE 802.11-1999, as amended (IEEE 802.11), is a WLAN standard.
IEEE 802.11i is an amendment regarding WLAN security.
IEEE 802.11 defines four cipher suites: WEP-40, WEP-104, TKIP, CCMP.
The first three cipher suites use the RC4 encryption algorithm.
The CCMP cipher suite uses the AES encryption algorithm.
The IEEE recommends not to use either WEP cipher suite.
IEEE 802.11 Robust Security Networks (RSN) use only TKIP and CCMP.
IEEE 802.11 defines 802.1X and PSK for RSN authentication and key management.
WPA and WPA2 are brand names owned by the Wi-Fi Alliance. Primarily they both mean "be happy, buy now, don't wait."
I hope this helps. Thanks. /criss