PROPORTIONAL TO

About this character

The proportional-to symbol (∝), encoded as U+221D, denotes a linear relationship between two variables, meaning one changes in direct correspondence with the other. Derived from the tilde, which itself indicates similarity, the symbol gained mathematical traction in the seventeenth century, often credited to William Oughtred or later writers. Beyond algebra and physics, where it expresses relationships like force proportional to acceleration, the character appears in typography as a variant of the tilde, used informally to mean "approximately" or in technical diagrams. In programming, it rarely appears as an operator but may serve as a readability marker in symbolic math libraries, while designers utilize it for visual balance in notation.

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Character

Copy the literal character when you need the glyph itself:∝