Posted by Bruce Kahl 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
: Does any one know the origin?
Dead is used in a vast number of figurative senses, some of which make sense and some of which are a bit more obscure. Following the OED for the development, the most obvious sense is 'deprived of life', the main sense, which has figurative uses such as 'asleep', 'numb or insensate', and '(of languages) no longer spoken'. From there we go to the sense 'deprived of a vital quality', such as '(of something normally burning) extinguished', as in "holding a dead cigar in his hand," '(of sound) muffled', '(of color) dull'. Then we have 'without vigor; lifeless; dull' ("it was a dead party").
These meanings are all fairly obvious developments. The next development is a larger one: broadly, 'absolute; complete; utmost', in reference to death being the final step in life. Your dead reckoning, or 'the dermination of geographical position based on internal factors only, rather than astronomical navigation', is an example of the "absolute" meaning; other are "dead giveaway" and "dead ringer." This sense is also used adverbially, meaning 'completely; absolutely; thoroughly', hence dead right and a number of other collocations, such as "dead perfect," "dead broke," and "dead serious." Other examples maintain some of the original sense: "dead tired" and "dead drunk" both imply 'to an extent suggesting death'. Deadeye in the nautical sense 'a wooden disk with holes through which ropes are drawn' is a shortening of the earlier deadman's eye, which is probably suggested by the appearance of the disk.
With some exceptions, most of the obscure formations can be explained by applying the "absolute; complete" meaning to the phrase.