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Infinity Symbol ∞ — Meaning, History and How to Type It

The complete guide to the infinity symbol. Its mathematical meaning, historical origin, and keyboard shortcuts for Mac, Windows, HTML and LaTeX.

The infinity symbol ∞ (U+221E) represents a quantity larger than any real number. Beyond mathematics it has become a popular motif for tattoos, jewellery, and social media — representing endlessness and eternal potential.

Mathematical Meaning

Introduced by English mathematician John Wallis in 1655, ∞ appears in calculus limits, improper integrals, and infinite series. In set theory, there are actually multiple infinities of different sizes (ℵ&sub0;, ℵ&sub1;, and so on — called cardinal numbers).

How to Type ∞

Windows: Alt + 236 on the numpad.

Mac: Option + 5. Simple and fast.

HTML: ∞ or ∞

LaTeX: \\infty

Origin of the ∞ Shape

The exact origin is debated. Theories include: a variant of the Roman numeral M (1000, meaning “very many”), a stylised Ouroboros (the ancient snake eating its tail), or simply an aesthetically pleasing closed curve chosen by Wallis. The lemniscate — the figure-eight shape on its side — had been studied by mathematicians before Wallis adopted it.

∞ in Popular Culture

The infinity symbol is one of the most popular tattoo designs worldwide, often placed on wrists or ankles. It appears in Marvel’s Infinity Gauntlet storyline, in jewellery representing eternal love, and as a logo for brands seeking to convey limitless quality.