This character is a Otro símbolo and is mainly used in the Katakana script.
The glyph is a square composition of the glyphs Katakana Letter Na, Katakana Letter No. Its East Asian Width is wide. In bidirectional text it is written from left to right. When changing direction it is not mirrored. This katakana joins with other adjacent katakana to form a word. U+3328 offers a line break opportunity at its position, except in some numeric contexts.
El Wikipedia tiene la siguiente información acerca de este punto de código:
Nano (symbol n) is a unit prefix meaning one billionth. Used primarily with the metric system, this prefix denotes a factor of 10−9 or 0.000000001. It is frequently encountered in science and electronics for prefixing units of time and length.
Examples
Three gold atoms lined up are about one nanometer (nm) long.
If a toy marble were scaled down to one nanometer wide, Earth would scale to about 1 meter (3.3 ft) wide.
One nanosecond (ns) is about the time required for light to travel 30 cm in air, or 20 cm in an optical fiber.
One nanometer per second (nm/s) is approximately the speed that a fingernail grows.
The prefix derives from the Greek νᾶνος (Latin nanus), meaning "dwarf". The General Conference on Weights and Measures (CGPM) officially endorsed the usage of nano as a standard prefix in 1960.
When used as a prefix for something other than a unit of measure (as for example in words like "nanoscience"), nano refers to nanotechnology, or means "on a scale of nanometres" (nanoscale).