Answer: oscillation

AnswerCrossword Clue
oscillationrepeated fluctuation above and below some mean value, as the pressure of a sound wave or the voltage of an alternating current, or a single such fluctuation between maximum and minimum values
oscillationsingle movement in one direction of a swinging body
oscillationact or instance of swinging to and fro
oscillationfluctuation between beliefs, opinions, conditions, etc.
oscillationthe action or state of oscillating