Unicode blocks are identified by unique names, which use only ASCII characters and are usually descriptive of the nature of the symbols, in English; such as "Tibetan" or "Supplemental Arrows-A".
(These constraints are intended to simplify the display of glyphs in Unicode Consortium documents, as tables with 16 rows labeled with the last hexadecimal digit of the code point.
[3] Each Unicode point also has a property called "General Category", that attempts to describe the role of the corresponding symbol in the languages or applications for whose sake it was included in the system.
Examples of General Categories are "Lu" (meaning upper-case letter), "Nd" (decimal digit), "Pi" (open-quote punctuation), and "Mn" (non-spacing mark, i.e. a diacritic for the preceding glyph).
Those subgroups are not "blocks" in the technical sense used by the Unicode consortium, and are named only for the convenience of users.