The symbol "∞" represents the concept of infinity, which refers to something that is limitless or unbounded. In mathematics, it is often used to describe quantities that grow without end, such as the number of natural numbers or the value of certain limits. Infinity is not a number in the traditional sense but rather an idea that helps us understand the behavior of numbers and functions. Infinity appears in various fields, including calculus, set theory, and philosophy. In calculus, it is used to describe the behavior of functions as they approach very large or very small values. In set theory, different sizes of infinity can be compared, such as the infinity of real numbers versus the infinity of integers.