cardinal number vs plethora

cardinal number

noun
  • A word that expresses a countable quantity; a cardinal numeral. 

  • A generalized kind of number used to denote the size of a set, including infinite sets. 

  • A number used to denote quantity; a counting number; a cardinal. 

plethora

noun
  • An excessive amount or number; an abundance. 

  • Excess of blood in the skin, especially in the face and especially chronically. 

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