In
Unicode, a
block is defined as one contiguous range of
code points. Blocks are named uniquely and have no
overlap. They have a starting code point of the form nnn0 and an ending code point of the form nnnF. A block explicitly can include code points that are
unassigned and non-characters. Code points not belonging to any of the named blocks, e.g. in the unassigned
planes 3–13, have the value block="No_block".