oxymoron vs synecdoche

oxymoron

noun
  • A figure of speech in which two words or phrases with opposing meanings are used together intentionally for effect. 

  • A contradiction in terms. 

synecdoche

noun
  • The use of this figure of speech. 

  • A figure of speech that uses the name of a part of something to represent the whole, or the whole to represent a part. 

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