fluctuation

noun3

1. •
   A motion like that of waves; a moving in this and that direction; an irregular rising and falling.

   • The rolling stock has been specially designed to meet the needs of the fluctuation of traffic in peak and off-peak periods. — 1959
2. •
   A wavering; unsteadiness.

   • fluctuations of prices
3. •
   In medicine, a wave-like motion or undulation of a fluid in a natural or abnormal cavity (e.g. pus in an abscess), which is felt during palpation or percussion.