0x221D

0x221D is the hexadecimal notation for the Unicode code point U+221D, which designates the mathematical symbol PROPORTIONAL TO (∝). The symbol is used in mathematical and scientific contexts to indicate that one quantity is proportional to another, commonly written as a ∝ b to express a proportional relationship.

In Unicode, the PROPORTIONAL TO symbol resides in the Mathematical Operators block (U+2200 to U+22FF) and is classified as a mathematical symbol (general category Sm). It is widely supported across modern fonts and rendering systems, with stylistic variations depending on the font. The symbol is also used in various disciplines, including physics and engineering, to convey proportionality without specifying a constant of proportionality.

In practical computing, 0x221D may be encountered when referring to the character by its hex code in source code, data formats, or configuration that denote Unicode scalars in hexadecimal. The corresponding Unicode code point U+221D has a decimal value of 8733, and in HTML can be represented by the numeric character reference ∝. In UTF-8, the code point is encoded using three bytes, reflecting its place within the BMP (Basic Multilingual Plane).