annotation vs datum

annotation

noun
  • A critical or explanatory commentary or analysis. 

  • Information relating to the genetic structure of sequences of bases. 

  • Metadata added to a document or program. 

  • A comment added to a text. 

  • The process of writing such comment or commentary. 

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. 

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