Which prefix indicates the color black in medical terminology?

The prefix that indicates the color black in medical terminology is "melan-." This prefix derives from the Greek word "melas," meaning black. It is commonly used in various medical terms to describe conditions or substances that are dark in color, such as "melanoma," which refers to a type of skin cancer that often appears as a dark mole due to the presence of melanin, the pigment responsible for the color of skin and hair.

The other prefixes do not relate to the color black: "cyan-" refers to the color blue, often used in terms related to oxygen deficiency (cyanosis), "leuko-" denotes the color white, typically associated with white blood cells (leukocytes), and "erythro-" signifies the color red, commonly seen in terms related to red blood cells (erythrocytes). Each of these prefixes accurately reflects its association with specific colors, distinguishing it clearly from "melan-" which unequivocally indicates black.