What term refers to a movement of the forearm that turns the palm downward?

The term that accurately describes the movement of the forearm that turns the palm downward is known as pronation. During pronation, the radius and ulna, the two long bones of the forearm, cross each other, allowing the palm to face downwards. This movement is commonly observed when making a gesture like returning your palms inwards while holding something.

To further clarify, supination, which is the opposite of pronation, refers to the movement that turns the palm upward. Inversion pertains to a movement that typically refers to the foot and involves turning the sole inward. Adduction describes a movement toward the midline of the body, which is not related to the orientation of the palm. Therefore, the correct term for turning the palm downward is pronation.