Infinity Symbol (∞)
Mathematical symbol representing an unbounded quantity or the concept of endlessness.
Mathematical/Western · 1655 – present
Integral Sign (∫)
Mathematical symbol denoting integration, introduced by Leibniz.
Description
The integral sign (∫) was introduced by Gottfried Wilhelm Leibniz in 1675 as an elongated 'S' (from the Latin 'summa', meaning sum). It denotes the operation of integration in calculus — the process of finding the area under a curve or the antiderivative of a function. The symbol appears in definite integrals (with upper and lower bounds) and indefinite integrals. Multiple integral signs (∬, ∭) denote double and triple integration over two- and three-dimensional regions respectively.
Origin & Cultural Context
Introduced by Gottfried Wilhelm Leibniz in his manuscript of 29 October 1675, first published in 1684.