I learnt a new term call Wi-Fi ... here is the detail of this new word:

Wi-Fi is the popular term for a high-frequency wireless local area network (WLAN) technology and standard that has gained acceptance in many companies as an alternative to a wired LAN. Wi-Fi is specified in the 802.11b specification from the Institute of Electrical and Electronics Engineers (IEEE) and is part of a series of wireless specifications together with 802.11, 802.11a, and 802.11g. All four standards use the Ethernet protocol and CSMA/CA (carrier sense
multiple access with collision avoidance) for path sharing.

The 802.11b (Wi-Fi) operates in the 2.4 GHz range offering data speeds up to 11 megabits per second. The modulation used in 802.11
has historically been phase-shift keying (PSK). The modulation method
selected for 802.11b is known as complementary code keying (CCK),
which allows higher data speeds and is less susceptible to multipath-propagation interference.

Unless adequately protected, a Wi-Fi wireless LAN can be susceptible
to access from the outside by unauthorized users, some of whom have
used the access as a free Internet connection! (The activity of
locating and exploiting security-exposed wireless LANs is commonly
known as war driving.) Companies that have a wireless LAN are urged
to add security safeguards such as the Wired Equivalent Privacy (WEP) encryption standard, the setup and use of a virtual private network (VPN) or IPsec, and a firewall or DMZ.