ferment

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Something, such as a yeast, bacterium, mold, or enzyme, that causes fermentation.
2. n. Fermentation.
3. n. A state of agitation or of turbulent change or development.
4. n. An agent that precipitates or is capable of precipitating such a state; a catalyst.
5. v. To produce by or as if by fermentation.
6. v. To cause to undergo fermentation.
7. v. To make turbulent; excite or agitate.
8. v. To undergo fermentation.
9. v. To be in an excited or agitated state; seethe.

Century Dictionary and Cyclopedia

1. n. A gentle boiling, or the internal motion of the constituent parts of a fluid.
2. n. That which is capable of causing fermentation. Ferments are of two kinds, organized and unorganized. Organized ferments belong to the lowest order of microscopic fungi. (See fermentation.) Unorganized or chemical ferments are substances capable of causing chemical changes in certain other substances without themselves being permanently changed in the process: as diastase, maltin, and ptyalin, which convert starch into a soluble modification or into sugar; pepsin, which dissolves proteids, forming peptones; emulsin, which resolves amygdalin into oil of bitter almonds, prussic acid, and dextrose.
3. n. Figuratively, commotion; heat; tumult; agitation: as, to put the passions in a ferment.
4. To cause to boil gently; cause ebullition in.
5. To cause fermentation in.
6. Figuratively, to set in agitation; excite; arouse.
7. To undergo fermentation.
8. Figuratively, to be in agitation; be excited, as by violent emotions or passions, or great problems.

Wiktionary

1. v. To react, using fermentation; especially to produce alcohol by aging or by allowing yeast to act on sugars; to brew.
2. v. To stir up, agitate, cause unrest.
3. n. Something, such as a yeast that causes fermentation.
4. n. A state of agitation or of turbulent change.
5. n. A catalyst.

GNU Webster's 1913

1. n. That which causes fermentation, as yeast, barm, or fermenting beer.
2. n. Intestine motion; heat; tumult; agitation.
3. n. rare A gentle internal motion of the constituent parts of a fluid; fermentation.
4. v. To cause ferment or fermentation in; to set in motion; to excite internal emotion in; to heat.
5. v. 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. To be agitated or excited by violent emotions.

WordNet 3.0

1. n. a substance capable of bringing about fermentation
2. n. a state of agitation or turbulent change or development
3. v. be in an agitated or excited state
4. v. cause to undergo fermentation
5. v. work up into agitation or excitement
6. n. a process in which an agent causes an organic substance to break down into simpler substances; especially, the anaerobic breakdown of sugar into alcohol
7. v. go sour or spoil