Which combining form indicates the color blue?

The combining form that indicates the color blue is "cyan/o." This term is derived from the Greek word "kyanos," which means dark blue. In medical terminology, "cyan/o" is often used to describe conditions related to a bluish discoloration of the skin or mucous membranes, a condition known as cyanosis. This can occur due to various factors, such as a lack of oxygen in the blood, often seen in respiratory disorders or circulatory issues.

The other combining forms represent different colors: "erythr/o" means red, "chlor/o" refers to green, and "melan/o" indicates black. Each of these terms is used in various medical contexts to describe different conditions or characteristics related to those specific colors. Understanding these combining forms is crucial for interpreting medical terminology accurately, as they provide important information about the nature of the conditions being described.