Wi-Fi has been in development since 1999 in an effort to connect devices wirelessly to private networks or the Internet. Wi-Fi (802.11) currently has 4 standards, developed in alphabetical order (a/b/g/n). Every new standard has what is called 'backwards compatibility' with previous standards.

for example:
An 802.11g laptop can connect to a router that has 802.11n, because the router has backwards compatibility with 802.11g.

Future Wi-Fi standards are still in the process of being ratified. Even though 802.11n is found in newer devices, it's still under development.