ascend vs entrain

ascend

verb
  • To move upward, to fly, to soar. 

  • To slope in an upward direction. 

  • To become higher in pitch. 

  • To succeed. 

  • To trace, search or go backwards temporally (e.g., through records, genealogies, routes, etc.). 

  • To lose one's virginity, especially of a man through unpaid and consensual sexual intercourse with a woman. 

  • To go up. 

  • To rise; to become higher, more noble, etc. 

entrain

verb
  • To draw along as a current does. 

  • To suspend small particles in the current of a fluid. 

  • To get into or board a railway train. 

  • To put aboard a railway train. 

  • To become trained or conditioned in a pattern of brain behavior. 

  • To set up or propagate a signal, such as an oscillation. 

  • To encarriage, to conjoin, to link; as in a series of entities, elements, objects or processes. 

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