mistake vs understand

mistake

verb
  • To understand wrongly, taking one thing or person for another. 

noun
  • An error; a blunder. 

  • A pitch which was intended to be pitched in a hard-to-hit location, but instead ends up in an easy-to-hit place. 

understand

verb
  • To believe, to think one grasps sufficiently despite potentially incomplete knowledge. 

  • To stand underneath, to support. 

  • To grasp a concept fully in one's mind, especially (of words, statements, art, etc.) to be aware of the meaning of and (of people) to be aware of the intent of. 

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