datum vs epistle

datum

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

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. 

epistle

noun
  • A letter, or a literary composition in the form of a letter. 

  • One of the letters included as a book of the New Testament. 

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