Sclerosis
Sclerosis (also sclerosus in the Latin names of a few disorders) is a hardening of tissue and other anatomical features; it may refer to: 

Sclerosis (medicine), a hardening of tissue
in zoology, a process which hardens forms sclerites, a hardened exoskeleton
in botany, a process which hardens plant tissue by adding fibers and sclereids, resulting in sclerenchyma
In economics, see: Eurosclerosis