spasm /spaz″əm/ [Gk, spasmos] , 1. an involuntary muscle contraction of sudden onset, such as habit spasms, hiccups, stuttering, or a tic. 2. a convulsion or seizure. 3. a sudden transient constriction of a blood vessel, bronchus, esophagus, pylorus, ureter, or other hollow organ. Compare stricture. See also bronchospasm, pylorospasm.
