incentive vs locomotive

incentive

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

  • Serving to kindle or set on fire. 

noun
  • Something that motivates, rouses, or encourages. 

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

locomotive

adj
  • Of or relating to locomotion. 

  • Of or relating to the power unit of a train which does not carry passengers or freight itself. 

noun
  • The power unit of a train that pulls the coaches or wagons. 

  • A country which drives the world economy by having a high level of imports, such as the United States. 

  • A cheer characterized by a slow beginning and a progressive increase in speed. 

  • A traction engine. 

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