Final answer:
The appropriate term for the amount of air remaining in the lungs after maximum expiration is Residual Volume (RV).
Step-by-step explanation:
The term the nurse should use to describe the amount of air remaining in the patient's lungs after maximum expiration is Residual Volume (RV). This is because RV is defined as the amount of air that remains in the lungs after a maximal exhalation and cannot be expelled. The lungs always contain residual volume, regardless of the force of expiration, which helps to prevent the alveoli from collapsing and maintains a constant level of gases in the lung.