A single number is assigned to each code element defined by the Unicode Standard. Each character is also assigned a unique name that specifies it and no other. The Unicode Standard groups characters together by scripts in code blocks. A script is any system of related characters. The standard retains the order of characters in a source set where possible.
Code blocks vary greatly in size.
For example, the Cyrillic code block does not exceed 256 code points, while the CJK code block has a range of thousands of code points. Code elements are grouped logically throughout the range of code points, called the codespace . The code space continues with Hiragana, Katakana, and Bopomofo. The unified Han ideographs are followed by the complete set of modern Hangul. The range of surrogate code points is reserved for use with UTF-16.