The "Less Than Sign" is a mathematical symbol represented as "<". It is used to compare two values, indicating that the value on the left is smaller than the value on the right. For example, in the expression "3 < 5", it shows that 3 is less than 5. This symbol is commonly used in various fields, including mathematics, computer science, and economics. It helps in understanding relationships between numbers and is essential for solving inequalities. The opposite of the less than sign is the "Greater Than Sign" (">"), which indicates that the left value is larger than the right value.