cryptology vs lexicon

cryptology

noun
  • Secret or enigmatical language. 

  • The science or study of mathematical, linguistic, and other coding patterns and histories. 

  • The practice of analysing encoded messages, in order to decode them. 

lexicon

noun
  • The vocabulary of a language. 

  • A dictionary of Classical Greek, Hebrew, Latin, or Aramaic. 

  • The lexicology of a programming language. (Usually called lexical structure.) 

  • A set of vocabulary specific to a certain subject. 

  • Any dictionary. 

  • A list thereof. 

  • A dictionary that includes or focuses on lexemes. 

  • The vocabulary used by or known to an individual. (Also called lexical knowledge.) 

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