conjoined vs synchronal

conjoined

adj
  • Combined. 

  • Joined together physically, of persons (conjoined twins), or things. 

  • Joined or bound together; united (in a relationship) 

synchronal

adj
  • Synchronous; simultaneous. 

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