noun (n)

• a quality of uniformity and lack of variation(noun.attribute)

  Synonym:
  evenness
  Antonym:
  unevenness, variability
  

  source: wordnet30
• the quality of being resistant to variation(noun.attribute)

  Synonym:
  invariableness, invariance
  Antonym:
  variability, variableness, variance
  

  source: wordnet30
• The quality of being invariable; invariableness; constancy; uniformity.(noun)

  source: webster1913