Which of the following roots means "dark" or "black"?

The root "melano-" comes from the Greek word "melas," meaning black or dark. It is commonly used in medical and scientific terminology to indicate a dark pigmentation or condition, such as in the context of melanocytes, which are cells that produce melanin, the pigment responsible for skin and hair color. This root effectively conveys the meaning related to darkness, aligning perfectly with the question's focus on the meaning of "dark" or "black." Understanding this root can aid in interpreting various terms encountered in medical or scientific readings.