Main Entry: amyo·tro·phic lateral sclerosis

Pronunciation: \ˌā-ˌmī-ə-ˈtrō-fik-, -ˈträ-\

Function: noun

Etymology: ²a- + my- + -trophic

Date: 1886

: a rare progressive degenerative fatal disease affecting the motor neurons, usually beginning in middle age, and characterized especially by increasing and spreading muscular weakness and atrophy —abbreviation ALS —called also Lou Gehrig's disease