'Invariance' definitions:

Definition of 'invariance'

From: WordNet
noun
The quality of being resistant to variation [syn: invariability, invariableness, invariance] [ant: variability, variableness, variance]
noun
The nature of a quantity or property or function that remains unchanged when a given transformation is applied to it; "the invariance of the configuration under translation"

Definition of 'Invariance'

From: GCIDE
  • Invariance \In*va"ri*ance\, n. (Math.) The property of remaining invariable under prescribed or implied conditions. --J. J. Sylvester. [1913 Webster]