The symbol for infinity, ∞ (U+221E) is called a leminscate, named for the shape of lemniscate curve from algebraic geometry which is is based on.
The word leminscate comes from the Latin lēmniscātus, meaning "decorated with ribbons". The use of leminscate in references to curves is attributed to Jacob Bernoulli. It was first used as a symbol for infinity by John Wallis in his 1655 paper De sectionibus conicis, but was used as a decorative symbol before. It is used for potential infinity rather than actual infinity as actual infinities have other symbols to represent them, such as ℕ or aleph numbers.
The exact reason Wallis chose the lemniscate is unclear, multiple theories have been put forth:
- Based on the Roman CIↃ which was used to represent 1000
- A variant of lower case omega, ω
Related Characters
- ♾ PERMANENT PAPER SIGN (U+267E)
- ⚭ MARRIAGE SYMBOL (U+26AD)