I. fer ‧ ment 1 /fəˈment $ fər-/ BrE AmE verb [intransitive and transitive]
[ Date: 1300-1400 ; Language: Old French ; Origin: fermenter , from Latin fermentum 'yeast' ]
if fruit, beer, wine etc ferments, or if it is fermented, the sugar in it changes to alcohol:
fermented fruit juice
—fermentation /ˌfɜːmenˈteɪʃ ə n $ ˌfɜːrmən-/ noun [uncountable]
II. fer ‧ ment 2 /ˈfɜːment $ ˈfɜːr-/ BrE AmE noun [uncountable]
a situation of great excitement or trouble in a country, especially caused by political change SYN turmoil
in ferment
In the 1960s, American society was in ferment.
political/intellectual/cultural etc ferment
the artistic ferment of the late sixth century