Real Dictionary

multiple sclerosis
uncountable noun: Multiple sclerosis is a serious disease of the nervous system, which gradually makes a person weaker, and sometimes affects their sight or speech. The abbreviation MS is also used.

multiple sclerosis in American English
a chronic disease in which there is scattered demyelination of the central nervous system: it may result in speech defects, loss of muscular coordination, etc.
noun: a chronic degenerative, often episodic disease of the central nervous system marked by patchy destruction of the myelin that surrounds and insulates nerve fibers, usually appearing in young adulthood and manifested by one or more mild to severe neural and

multiple sclerosis in British English
noun: a chronic progressive disease of the central nervous system characterized by loss of some of the myelin sheath surrounding certain nerve fibres and resulting in speech and visual disorders, tremor, muscular incoordination, partial paralysis, etc