amyotrophic lateral sclerosis: Meaning and Definition of

a•my•o•troph'ic lat'eral sclero'sis

Pronunciation: (ā"mī-u-trof'ik, -trō'fik, ā-mī"u-), [key]
— Pathol. Pathol.
  1. an incurable disease of unknown cause in which progressive degeneration of motor neurons in the brain stem and spinal cord leads to atrophy and eventually complete paralysis of the voluntary muscles. Abbr.: ALS Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.