What does the term 'pallor' refer to in a medical context?

In a medical context, the term 'pallor' specifically refers to a noticeable paleness of the skin, often due to a decrease in blood flow or a lower-than-normal level of red blood cells. This paleness can indicate various underlying health conditions, such as anemia, shock, or other medical issues that impact circulation or oxygenation. Recognizing pallor in a patient can serve as an important clinical sign, prompting further evaluation to identify the cause. The other choices describe different skin conditions: increased redness may indicate inflammation or irritation, yellowing of the skin points towards jaundice, and swelling can indicate edema or other reactions in the skin. Therefore, the correct answer aligns with the medical definition and implications of pallor.