that which causes fermentation, as yeast, barm, or fermenting beer.-intestine motion; heat; tumult; agitation.-a gentle internal motion of the constituent parts of a fluid; fermentation.-to cause ferment of fermentation in; to set in motion; to excite internal emotion in; to heat.-to undergo fermentation; to be in motion, or to be excited into sensible internal motion, as the constituent oarticles of an animal or vegetable fluid; to work; to effervesce.-to be agitated or excited by violent emotions.