plaintiff vs respondent

plaintiff

noun
  • A party bringing a suit in civil law against a defendant; accuser. 

respondent

noun
  • A defendant, especially in a case instituted by a petition or in appellate and divorce proceedings. 

  • A person replying to a questionnaire. 

  • One who responds; one who replies. 

adj
  • Disposed or expected to respond; answering; according; corresponding. 

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