- 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.
- a hardening of a tissue or cell wall by thickening or lignification.
- 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
- the hardening of a plant cell wall or tissue by the deposition of lignin
- a debilitating lack of progress or innovation within an institution or organization
