outflow vs progression

outflow

noun
  • Any outward movement. 

  • Something that flows out of a sewage treatment plant. 

  • The process of flowing out. 

  • A fluid that flows out. 

  • A stream of gaseous material emanating from an active galactic nucleus. 

  • The part of a system that allows material to flow out. 

verb
  • To flow outward. 

progression

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

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

  • chord progression 

  • The act of moving from one thing to another. 

  • Development, increase, evolution. 

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

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