progression vs travelling

progression

noun
  • The act of moving from one thing to another. 

  • A sequence obtained by adding or multiplying each term by a constant. 

  • chord progression 

  • The act of moving forward or proceeding in a course; motion onward. 

  • Development, increase, evolution. 

  • The making an exercise more exerting by manipulating the details of its performance like loaded weight, range of motion, angle, speed. 

travelling

noun
  • The act of one who travels; a journey. 

adj
  • That travels (with one) 

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