A step function is a type of mathematical function that changes its value at specific intervals, resembling a staircase. It is defined by a series of constant values over certain ranges, making it easy to visualize. For example, a step function might take the value of 1 for inputs between 0 and 2, then jump to 2 for inputs between 2 and 4. Step functions are commonly used in various fields, including engineering, economics, and computer science. They can model situations where a quantity changes suddenly, such as in digital signals or when calculating taxes that apply to different income brackets.