1.nounA motion like that of waves; a moving in this and that direction.
"the fluctuations of the sea"
2.nounA wavering; unsteadiness.
"fluctuations of opinion"
3.nounIn 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.