1. (n.) That which causes fermentation, as yeast, barm, or fermenting beer.

2. (n.) Intestine motion; heat; tumult; agitation.

3. (n.) A gentle internal motion of the constituent parts of a fluid; fermentation.

4. (n.) To cause ferment of fermentation in; to set in motion; to excite internal emotion in; to heat.

5. (v. i.) To undergo fermentation; to be in motion, or to be excited into sensible internal motion, as the constituent particles of an animal or vegetable fluid; to work; to effervesce.

6. (v. i.) To be agitated or excited by violent emotions.