1590s, "vigorous;" 1680s, "widely accepted, generally current," present-participle adjective from prevail (v.). Related: Prevailingly.
Prevalent and prevailing are sometimes the same, and in two senses, that of exceeding in strength, as the prevalent (or prevailing) opinion was against action, and that of existing widely, as scarlet fever is a prevalent (or prevailing) distemper. The habitual is more likely to be expressed by prevalent ; the present or actual, sometimes the temporary, by prevailing : as, the prevailing fashion. [Century Dictionary]