oratory vs public speaking

oratory

noun
  • The art of public speaking, especially in a formal, expressive, or forceful manner. 

  • Eloquence; the quality of artistry and persuasiveness in speech or writing. 

  • A Roman Catholic chapel; a building for public or private worship that is not a parish church. 

  • A private chapel or prayer room. 

  • A Catholic church belonging to the Oratory of Saint Philip Neri. 

public speaking

noun
  • oratory (art of public speaking) 

  • act of speaking to a group of people in a structured manner 

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