datum vs presupposition

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. 

presupposition

noun
  • An assumption made beforehand; a preliminary conjecture or speculation. 

  • The act of presupposing. 

  • An assumption or belief implicit in an utterance or other use of language. 

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