from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A method of estimating the position of an aircraft or a ship without astronomical observations, as by applying to a previously determined position the course and distance traveled since.
- n. Predictive calculation based on inference; guesswork.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A method of estimating the position of a ship or aircraft by applying estimates of the distance and direction travelled to a previously known position. In respect to ships/boats, it excludes the effect of wind and current on the vessel. Compare with estimated position. Abbreviation: DR
from the GNU version of the Collaborative International Dictionary of English
- adj. the method of determining the place of a ship from a record kept of the courses sailed as given by compass, and the distance made on each course as found by log, with allowance for leeway, etc., without the aid of celestial observations.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. navigation without the aid of celestial observations
- n. an estimate based on little or no information
Possibly alteration of ded., abbr. of deduced, from deduce, to trace from the beginning; see deduce.(American Heritage® Dictionary of the English Language, Fourth Edition)
Sailing one direction, drifting another direction, to say nothing of the set of the current in some third direction, makes a resultant which dead reckoning can never calculate.