Pallor refers to:

Pallor is the medical term used to describe an unhealthy paleness of the skin, which can be a sign of various underlying health issues such as anemia, shock, or other conditions that affect blood flow or red blood cell levels. It indicates a decrease in blood volume or variations in blood supply, leading to a lighter appearance of the skin compared to its normal color. This symptom can also be reflective of a person's overall health status, making it clinically significant for assessments.

The other choices describe different skin conditions or appearances that do not represent the definition of pallor. Reddish discoloration refers to erythema or flushing, which has distinct causes, while non-affected skin represents normal skin appearance without any pathological changes. A healthy glow suggests vibrant skin color, which is the opposite of what pallor signifies. Therefore, recognizing pallor is essential in clinical settings for diagnosing and addressing potential health concerns.