Which combining form is associated with the color blue?

The combining form associated with the color blue is "cyan/o." This term originates from the Greek word "kyanos," which means dark blue or blue-green. In medical terminology, "cyanosis" refers to a bluish discoloration of the skin or mucous membranes due to inadequate oxygenation of the blood, clearly linking the combining form "cyan/o" to the concept of the color blue in a health context.

The other combining forms have different meanings: "leuk/o" pertains to the color white, commonly used in terms like "leukocyte," which refers to white blood cells. "melan/o" relates to the color black or dark and is found in terms such as "melanoma," a type of skin cancer characterized by dark pigmentation. Lastly, "poli/o" is associated with the color gray, often used in terms like "poliomyelitis," which refers to a viral infection affecting gray matter in the spinal cord. Each of these terms serves a specific purpose in medical terminology, but "cyan/o" is distinctively the one that represents the color blue.