fluctuation

from The Century Dictionary.

• noun A motion like that of waves; a waving; movement in different directions: as, the fluctuations of the sea.
• noun Alternating action or movement; a wavering or varying course; mutation: as, the fluctuations of prices or of the funds; fluctuations of opinion.
• noun In medicine, the alternating motion of pus or other fluids perceptible on palpation.
• noun Synonyms and Oscillation, vacillation.
• noun Produce; fruit.

from the GNU version of the Collaborative International Dictionary of English.

• noun A motion like that of waves; a moving in this and that direction.
• noun A wavering; unsteadiness
• noun (Med.) The motion or undulation of a fluid collected in a natural or artifical cavity, which is felt when it is subjected to pressure or percussion.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A motion like that of waves; a moving in this and that direction.
• noun A wavering; unsteadiness.
• noun The motion or undulation of a fluid collected in a natural or artificial cavity, which is felt when it is subjected to pressure or percussion.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a wave motion
• noun the quality of being unsteady and subject to changes
• noun an instance of change; the rate or magnitude of change