apprehension vs datum

apprehension

noun
  • Perception; the act of understanding using one's intellect without affirming, denying, or passing any judgment 

  • Opinion; conception; sentiment; idea. 

  • Anticipation, especially of unfavorable things such as dread or fear or the prospect of something unpleasant in the future. 

  • The faculty by which ideas are conceived or by which perceptions are grasped; understanding. 

  • The physical act of seizing or taking hold of (something); seizing. 

  • The act of seizing or taking by legal process; arrest. 

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 apprehension and datum occurred in a corpus of books? (source: Google Ngram Viewer )