lag vs retardation

lag

noun
  • Delay; latency. 

  • A method of deciding which player shall start. Both players simultaneously strike a cue ball from the baulk line to hit the top cushion and rebound down the table; the player whose ball finishes closest to the baulk cushion wins. 

  • A stave of a cask, drum, etc.; especially (engineering) one of the narrow boards or staves forming the covering of a cylindrical object, such as a boiler, or the cylinder of a carding machine or steam engine. 

  • A gap, a delay; an interval created by something not keeping up; a latency. 

  • One who lags; that which comes in last. 

  • A bird, the greylag. 

  • The fag-end; the rump; hence, the lowest class. 

  • A prisoner, a criminal. 

verb
  • To respond slowly. 

  • To fail to keep up (the pace), to fall behind. 

  • To cause to lag; to slacken. 

  • To cover (for example, pipes) with felt strips or similar material (referring to a time lag effect in thermal transfer). 

adj
  • Late. 

  • Last made; hence, made of refuse; inferior. 

retardation

noun
  • The act of diminishing the rate of speed. 

  • The distance by which one wave is behind another. 

  • The extent to which anything is retarded; the result of any retarding or delay; mental, social, or physical slowness. 

  • Deceleration; reduction in the magnitude of velocity. 

  • That which retards; an obstacle; an obstruction. 

  • Extreme stupidity. 

  • A decrease in the speed of telegraph signalling. 

  • A suspension which resolves upwards. 

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