Give the suffix form (be careful not to give the combining form) meaning the hardening of.

The suffix that means "the hardening of" is -sclerosis. This suffix is derived from the Greek word "sklerosis," which refers to a condition characterized by hardening in biological tissues. It is commonly used in medical terminology to describe various diseases and conditions where tissues become abnormally hardened.

For example, in the term "arteriosclerosis," the suffix "-sclerosis" indicates the hardening of the arteries. Similarly, "multiple sclerosis" refers to a disease marked by hardening of the myelin sheath surrounding nerves in the central nervous system. Understanding the suffix is crucial in comprehending the nature of the disease or condition being described. Thus, when identifying or creating terms related to hardening, "-sclerosis" is the appropriate choice.