expound vs noun

expound

verb
  • To set out the meaning of; to explain or discuss at length 

  • To make a statement, especially at length. 

noun

verb
  • To convert a word to a noun. 

noun
  • A word that functions as the name of a specific object or set of objects, such as person, animal, place, thing, phenomenon, substance, quality, or idea; one of the basic parts of speech in many languages, including English. 

  • An object within a user interface to which a certain action or transformation (i.e., verb) is applied. 

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