Zy*motic (?), a. [Gr. causing to ferment, fr. to ferment, ferment, leaven.]1. Of, pertaining to, or caused by, fermentation.2. (Med.) Designating, or pertaining to, a certain class of diseases. See Zymotic disease, below.Zymotic disease (Med.), any epidemic, endemic, contagious, or sporadic affection which is produced by some morbific principle or organism acting on the system like a ferment.