explain vs express

explain

verb
  • To make plain, manifest, or intelligible; to clear of obscurity; to illustrate the meaning of. 

  • To give a valid excuse for past behavior. 

  • To make something plain or intelligible. 

express

verb
  • To convey or communicate; to make known or explicit. 

  • To transcribe deoxyribonucleic acid into messenger RNA. 

  • To press, squeeze out (especially said of milk). 

  • To translate messenger RNA into protein. 

noun
  • An express office. 

  • That which is sent by an express messenger or message. 

  • A mode of transportation, often a train, that travels quickly or directly. 

  • A service that allows mail or money to be sent rapidly from one destination to another. 

  • An express rifle. 

  • A messenger sent on a special errand; a courier. 

adv
  • Moving or operating quickly, as a train not making local stops. 

adj
  • Truly depicted; exactly resembling. 

  • Moving or operating quickly, as a train not making local stops. 

  • Specific or precise; directly and distinctly stated; not merely implied. 

  • Providing a more limited but presumably faster service than a full or complete dealer of the same kind or type. 

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