Closed-loop poles refer to the poles of the transfer function of a system when it is in a closed-loop configuration. In control theory, a closed-loop system incorporates feedback from the output of the system to adjust the input, allowing for regulation and stabilization of the system's behavior. The poles of the closed-loop transfer function determine the stability and transient response characteristics of the system. The location of these poles in the complex plane indicates whether the system is stable, marginally stable, or unstable, and influences factors such as settling time, overshoot, and damping of the system's response to input signals.