datum vs memo

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. 

memo

noun
  • A short note; a memorandum. 

  • A record of partial results that can be reused later without recomputation. 

verb
  • To record something; to make a note of something. 

  • To send someone a note about something, for the record. 

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