fluctuation (n.)youdaoicibaDictYouDict[fluctuation 词源字典]
mid-15c., from Old French fluctuacion (12c.) or directly from Latin fluctuationem (nominative fluctuatio) "a wavering, vacillation," noun of action from past participle stem of fluctuare "to undulate, to move in waves," from fluctus "a wave, billow, surge, a flowing," from past participle of fluere "to flow" (see fluent).[fluctuation etymology, fluctuation origin, 英语词源]