sklə̇ˈrōsə̇s noun
( plural sclero·ses -ōˌsēz)
Etymology: Middle English sclirosis, from Medieval Latin, from Greek sklērōsis, from sklēroun to harden (from sklēros hard) + -sis — more at skeleton
1.
a. : pathological hardening of tissue produced by overgrowth of fibrous tissue and other changes (as in arteriosclerosis) or by increase in interstitial tissue and other changes (as in multiple sclerosis)
b. : any of various diseases characterized by sclerosis — usually used in combination; see arteriosclerosis , multiple sclerosis
2. : hardening of plant cell walls by thickening or by deposition of lignin