Emily Dickinson Lexicon

SPASM, n. [L. spasmus; Gr. σπασμα, from σπαω, to draw.]

An abnormal, sudden, and more or less violent but brief contraction of one or more muscles, or muscular fibers. Spasm is either clonic or tonic. In clonic spasm, the muscles or muscular fibers contract and relax alternately in very quick succession, producing the appearance of agitation, as in epilepsy. In tonic spasm, the muscles or muscular fibers contract in a steady and uniform manner, and remain contracted for a comparatively long time, as in tetanus. Some cases of spasm appear to be intermediate between these two varieties.