'ALS' originates from the medical term 'Amyotrophic Lateral Sclerosis', where 'amyotrophic' means 'no muscle nourishment', 'lateral' refers to the areas in the spinal cord where portions of the nerve cells that signal and control the muscles are located, and 'sclerosis' means 'scarring' or 'hardening'.

The term 'ALS' was derived from the Greek words 'a' (no), 'myo' (muscle), and 'trophic' (nourishment), combined with 'lateral' and 'sclerosis' to describe the disease's characteristics.

Initially, it was used to describe the specific medical condition, and this meaning has remained consistent in modern usage.