datum vs diary

datum

noun
  • 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. 

  • A fact known from direct observation. 

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

diary

noun
  • A daily log of experiences, especially those of the writer. 

  • A personal organizer or appointment diary. 

verb
  • To keep a diary or journal. 

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