heterogeneity vs multeity

heterogeneity

noun
  • A composition of diverse parts. 

  • Diversity 

  • The quality of a substance which is not uniform. 

multeity

noun
  • manifoldness; multiplicity; the quality of being many. 

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