The "n-th derivative" refers to the process of taking the derivative of a function multiple times. The first derivative measures the rate of change of a function, while the second derivative indicates how that rate itself changes. Continuing this process, the n-th derivative provides insights into the behavior of the function at higher levels of change. In mathematical notation, if f(x) is a function, the n-th derivative is often denoted as f^(n)(x) . This concept is crucial in fields like calculus, physics, and engineering, where understanding the behavior of functions is essential for modeling and problem-solving.