Unicode
Unicode is a standard for encoding and sorting text characters, with a current limit of 4,294,967,296 different characters, of which less than a million have been assigned. There are various different encodings under the Unicode standard, such as UTF-8, UCS-2, UCS-4, and UTF-16 (same as UCS-2 but with an addition of delegates to allow access to various code points outside the 0-65535 range). Most modern software that uses Unicode for text use either UTF-8 or UTF-16. (Interesting tidbit: under the hood, Windows NT and its successors use UTF-16 for text strings, and the ANSI versions of Win32 API functions merely translate text input and output between the local code page and UTF-16.)
