appreciation vs datum

appreciation

noun
  • Accurate perception; true estimation. 

  • A rise in value. 

  • The act of appreciating. 

  • A fair valuation or estimate of merit, worth, weight, etc.; recognition of excellence; gratitude and esteem. 

datum

noun
  • A fact known from direct observation. 

  • A premise from which conclusions are drawn. 

  • A floating reference point, or SLDMB, used to evaluate surface currents in a body of water. Often employed by coastal search and rescue. 

  • A fixed reference point or set of reference points which precisely define a system of measurement or a coordinate system. 

verb
  • To provide missing data points by using a mathematical model to extrapolate values that are outside the range of a measuring device. 

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