incentive vs promo

incentive

noun
  • Something that motivates, rouses, or encourages. 

  • A bonus or reward, often monetary, to work harder. 

adj
  • Inciting; encouraging or moving; rousing to action; stimulating. 

  • Serving to kindle or set on fire. 

promo

noun
  • an interview or monologue intended to promote a character or an upcoming match. 

verb
  • To promote; to publicize. 

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