Dead reckoning
Posted by ESC on February 24, 2000
In Reply to: Dead reckoning posted by jeff waite on February 23, 2000
: A phrase used in navigation when the pilot/captain is not using
any navigation aids other than a map, clock, compass and speed indications,
as compared to more modern devises like radio beacons or now GPS
systems, etc.
: Does any one know the origin?
"Dead" as an adverb means "absolutely, completely," according to The Barnhart Concise Dictionary of Etymology by Robert K. Barnhart. That's the only clue I could find.