fluctuation (n.)

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).