consistent vs invariant

consistent

adj
  • Of a regularly occurring, dependable nature. 

  • Of a set of statements: such that no contradiction logically follows from them. 

  • Compatible, accordant. 

noun
  • A kind of penitent who was allowed to assist at prayers, but was not permitted to receive the holy sacraments. 

  • Objects or facts that are coexistent, or in agreement with one another. 

invariant

adj
  • not varying; constant 

  • Neither covariant nor contravariant. 

  • Unaffected by a specified operation (especially by a transformation) 

noun
  • An invariant quantity, function etc. 

How often have the words consistent and invariant occurred in a corpus of books? (source: Google Ngram Viewer )