heed vs observation

heed

noun
  • Careful attention. 

verb
  • To mind; to regard with care; to take notice of; to attend to; to observe. 

observation

noun
  • A judgement based on observing. 

  • The act of noting and recording some event; or the record of such noting. 

  • A remark or comment. 

  • A realization of a random variable. 

  • Performance of what is prescribed; adherence in practice; observance. 

  • A regime under which a subject is routinely observed. 

  • Philosophically as: the phenomenal presence of human being existence. 

  • The act of observing, and the fact of being observed (see observance) 

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