Unicode is a 16-bit character encoding system established by the Unicode Consortium. Their home page is http://unicode.org.
Unicode 2.0 has 38,885 encoded characters and includes script for 25 languages, including Japanese. Although Unicode is used for internal encoding in Windows NT and Java, it has not become popular for character displays or for input. Although, it is a potentially powerful standard, can display multiple language scripts on the same screen, and lends itself better to an internationalized Linux system than EUC, its lack of popular support in desktop applications makes it more of a technical curiousity than an essential part of a Linux system.
More information on Unicode can be found in the appendix in section 15.3. There are a number of screen shots, including a screen shots from Netscape Navigator 4.0 and a Unicode editor.