Keitai is an abbreviation of "
keitai denwa" and means "
portable phone" in
Japanese. It's usually being written in
Kanji or, to put more emphasize on the word, in
Katakana.
However, everybody who looks at today's streets and public places in Japan (and especially Tokyo), will soon realize that keitai in Japan are much more then an ordinary portable phone.
People use these little sleek and powerful mini-computers to play wireless Java games, read and send email, browse the mobile Internet on large high resolution color TFT screens (most popular coming in the shape of i-mode), listen to downloaded music (with the quality of a portable disc player) and watch streaming video clips (like the movie trailer of "Planet of the Apes").
Oh yes, and from time to time, people even still use their keitai for actually placing and receiving calls, you know, this old fashioned voice function that portable phones originally have been made for ;-)
The newest kids in future town Tokyo even have a cool video phone function, where one can see the other speaking party on the phone display, in real time. Star Trek is just around the corner, I'd say.