allegory vs onomatopoeia

allegory

noun
  • A symbolic representation which can be interpreted to reveal a hidden meaning, usually a moral or political one. 

  • A narrative in which a character, place, or event is used to deliver a broader message about real-world issues and occurrences. 

  • A picture, book, or other form of communication using such representation. 

  • A category that retains some of the structure of the category of binary relations between sets, representing a high-level generalisation of that category. 

onomatopoeia

noun
  • The property of a word of sounding like what it represents. 

  • The use of language whose sound imitates that which it names. 

  • A word that sounds like what it represents, such as "gurgle," "stutter," or "hiss". 

  • A word that appropriates a sound for another sensation or a perceived nature, such as "thud", "beep", or "meow"; an ideophone, phenomime. 

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