Emily Dickinson Lexicon

FER'MENT, n. [L. fermentum, from ferveo, to boil. See Fervent.]

1. A gentle boiling; or the internal motion of the constituent parts of a fluid. [In this sense it is rarely used. See Fermentation.]
2. Intestine motion; heat; tumult; agitation; as, to put the passions in a ferment; the state or people are in a ferment. Subdue and cool the ferment of desire. Rogers.
3. That which causes fermentation, as yeast, barm, or fermenting beer.