Custodial interrogation refers to the questioning of a suspect by law enforcement after the suspect has been taken into custody or deprived of their freedom in a significant way. This process is critical because it often involves the potential for coercion, which is why legal protections, such as the Miranda rights, are invoked to ensure that the suspect is aware of their rights and understands the implications of speaking with law enforcement. These rights serve to safeguard the suspect's Fifth Amendment right against self-incrimination during this vulnerable phase of legal proceedings.