sclerosis

American  

[skli-roh-sis] / sklɪˈroʊ sɪs /

noun

plural

scleroses

1. Pathology. a hardening or induration of a tissue or part, or an increase of connective tissue or the like at the expense of more active tissue.

2. Botany. a hardening of a tissue or cell wall by thickening or lignification.

---

sclerosis British  

/ sklɪəˈrəʊsɪs /

noun

1. pathol a hardening or thickening of organs, tissues, or vessels from chronic inflammation, abnormal growth of fibrous tissue, or degeneration of the myelin sheath of nerve fibres, or (esp on the inner walls of arteries) deposition of fatty plaques Compare arteriosclerosis atherosclerosis multiple sclerosis

2. the hardening of a plant cell wall or tissue by the deposition of lignin

3. a debilitating lack of progress or innovation within an institution or organization

---

Other Word Forms

• sclerosal adjective

Etymology

Origin of sclerosis

1350–1400; Middle English < Medieval Latin < Greek sklḗrōsis hardening. See scler-, -osis

Example Sentences

Its aging multiple sclerosis franchise continues to suffer losses that must be offset by newer drugs.

From Barron's • Mar. 31, 2026

When Nina Sparks was diagnosed with multiple sclerosis in 2021, she decided very quickly it was going to be the making of her.

From BBC • Mar. 5, 2026

With fenebrutinib, the company aims to launch a new oral treatment for multiple sclerosis that offers both greater convenience to patients relative to Ocrevus.

From The Wall Street Journal • Mar. 5, 2026

Actor Eric Dane, who rose to fame as Dr. Mark Sloan on “Grey’s Anatomy,” died Thursday afternoon following a battle with amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig’s disease.

From Salon • Feb. 20, 2026

One doctor suggested she might have multiple sclerosis; so many of her symptoms seemed to indicate some kind of degenerative illness.

From "Zeitoun" by Dave Eggers