Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
ferment, foment (nn., vv.)
Intransitive ferment means “to be in a state of fermentation,” and transitive ferment means “to cause to ferment,” “to work into a state of agitation, to agitate or excite.” This figurative sense overlaps with the verb foment, the most central literal sense of which is “to promote the growth or development of,” but which also means figuratively “to instigate, to stir up, to incite”: One of my chief pleasures in high school was to ferment [foment] rebellion in the classroom. The noun ferment refers to the process of fermentation and figuratively to “a state of agitation or excitement.” Foment as a noun is rare and synonymous with fomentation, the more commonly encountered noun; its literal senses refer to the application of hot substances and moist heat to reduce pain and the figurative sense is again “the act of fomenting” or “instigation.”
