"tough outer membrane surrounding the brain and the spinal cord," c. 1400, from Medieval Latin dura mater cerebri, literally "hard mother of the brain," a loan-translation of Arabic umm al-dimagh as-safiqa, literally "thick mother of the brain." "In Arabic, the words 'father,' 'mother,' and 'son' are often used to denote relationships between things" [Klein].
sclerosis of the spinal cord, causing atrophy of the muscles, 1874, in translations from French. Amyotropic is compounded from Greek elements: a- "not, without" (see a- (3)) + combining form of mys "muscle" (see muscle (n.)) + trophikos "feeding," from trophe "nourishment" (see -trophy). Also ALS, and often known in U.S. as Lou Gehrig's disease, after the New York Yankees baseball player who was diagnosed with it in 1939 and died of it in 1941.