What does the word lag mean?

Usage examples for lag

  1. But the greater the elevation of the object the wider its orbit round the Earth's centre, and the longer each degree; so that moving eastward only a thousand miles an hour, I should constantly lag behind a point on the Earth's surface, and should not reach the midnight meridian till somewhat later. – Across the Zodiac by Percy Greg
  2. Indeed, because of slow recovery in output of German coal, there is yet considerable lag in the supply available for European countries. – The Economic Aspect of Geology by C. K. Leith
  3. Occasionally a man would begin to lag, but some one always stopped to give him a hand. – In the Heart of a Fool by William Allen White