datum vs inscription

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. 

inscription

noun
  • The act of inscribing. 

  • Text carved on a wall or plaque, such as a memorial or gravestone. 

  • Words written in the front of a book as a dedication. 

  • The text on a coin. 

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