propulsion vs redundancy

propulsion

noun
  • The action of driving or pushing, typically forward or onward; a propulsive force or impulse. 

redundancy

noun
  • The state of being redundant 

  • Duplication of parts of a message to guard against transmission errors. 

  • surplusage inserted in a pleading which may be rejected by the court without impairing the validity of what remains. 

  • A superfluity; something redundant or excessive; a needless repetition in language 

  • Duplication of components or circuits to provide survival of the total system in case of failure of single components. 

  • The state of being unemployed because one's job is no longer necessary; the dismissal of such an employee; a layoff. 

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