"morbid hardening of the tissue," late 14c., from Medieval Latin sclirosis "a hardness, hard tumor," from Greek sklerosis "hardening," from skleros "hard" (see sclero-). Figurative use by 1954.
sclerosis scle·ro·sis (sklə-rō'sĭs)
n. pl. scle·ro·ses (-sēz)
The hardening of a tissue or part due to chronic inflammation.
A thickening or hardening of a body part or system especially from excessive formation of fibrous interstitial or glial tissue.
Any of various diseases characterized by thickening or hardening, such as arteriosclerosis.