Definition of fermentation

• n. - The process of undergoing an effervescent change, as by the action of yeast; in a wider sense (Physiol. Chem.), the transformation of an organic substance into new compounds by the action of a ferment, either formed or unorganized. It differs in kind according to the nature of the ferment which causes it.
• n. - A state of agitation or excitement, as of the intellect or the feelings.