180-degree feedback is when an individual invites feedback from one particular area of their working lives, most commonly being a manager's direct reports. This feedback is usually based on a set of competencies or behavioral statements and requires the individual to also complete a self-assessment.
In its purest form, the process is known as 360-degree feedback, which includes an individual receiving feedback from all aspects of their working life, i.e., peers, direct reports, line manager, customers, suppliers, and comparing this to your own self-perception.