'Variability' definitions:

Definition of 'variability'

From: WordNet
noun
The quality of being subject to variation [syn: variability, variableness, variance] [ant: invariability, invariableness, invariance]
noun
The quality of being uneven and lacking uniformity [syn: unevenness, variability] [ant: evenness, invariability]

Definition of 'Variability'

From: GCIDE
  • Variability \Va`ri*a*bil"i*ty\, n. [Cf. F. variabilit['e].]
  • 1. The quality or state of being variable; variableness. [1913 Webster]
  • 2. (Biol.) The power possessed by living organisms, both animal and vegetable, of adapting themselves to modifications or changes in their environment, thus possibly giving rise to ultimate variation of structure or function. [1913 Webster]