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.

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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

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Other Word Forms

• sclerosal
  adjective

Etymology

Origin of sclerosis

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

Explanation

Someone is diagnosed with the condition sclerosis when a part of their body becomes unusually hardened. A diet that's too high in cholesterol can cause sclerosis of the arteries. In many cases of sclerosis, the stiffening of tissue in organs, nerves, or arteries happens when it's gradually replaced with harder connective tissue. One of the most common forms of sclerosis is called multiple sclerosis, or MS. In this disorder, nerve cells in the spinal cord and brain are affected. Eventually patients with multiple sclerosis experience lack of coordination, numbness, and other symptoms. The Greek root is skleros, or "hard."

Example Sentences

Funding for the study was provided by the National Multiple Sclerosis Society.

From Science Daily • Jan. 6, 2026

"We are comparably sized to Multiple Sclerosis and Parkinson's, and yet our visibility and the services that we do receive pale in significance," she said.

From BBC • Oct. 7, 2025

Vie has built a coalition of nonprofits, including the Scleroderma Research Foundation and the National Multiple Sclerosis Society, with a goal of knitting together expertise in these diseases, said Evnin, a senior adviser to Vie.

From The Wall Street Journal • Jul. 9, 2025

The 5-year project, Accelerating Medicines Partnership in Amyotrophic Lateral Sclerosis, announced this week, is intended to centralize current and future ALS data sets and to identify therapeutic targets and biomarkers enabling early diagnosis.

From Science Magazine • May 22, 2024

Sclerosis of the arteries and other symptoms of heart failure, warned him during this autumn of 1895 that he was "descending the shady side of the hill."

From Lafcadio Hearn by Kennard, Nina H.