Definition

1. Noun:
   • Navigation without the aid of celestial observations: A method of calculating one's current position in navigation by using a previously determined position, and advancing that position based upon known or estimated speeds over elapsed time and course.
   • An estimate based on little or no information: A guess or calculation made without having all the necessary facts or data.

Usage Examples

• Noun (Navigation):
  • The sailors used dead reckoning to navigate through the fog when the stars were not visible.
  • Before modern GPS, pilots often relied on dead reckoning for long flights over featureless terrain.
• Noun (Estimate):
  • Without the sales report, my budget forecast is just dead reckoning.
  • He gave a dead reckoning of the project's cost, admitting it was a rough guess.

Advanced Usage

• "by dead reckoning": Using the method of dead reckoning.
  • The ship sailed by dead reckoning for three days after the storm damaged its instruments.
• Used to emphasize the speculative or non-scientific nature of an estimate.
  • The politician's promise was based more on dead reckoning than on economic data.

Variants and Related Words

• Deduced Reckoning (DR): A formal synonym for the navigational meaning of dead reckoning.
• Guesstimate (n): An informal estimate based on a mixture of guesswork and calculation, similar to the second meaning.
• Pilotage (n): Navigation by visual reference to landmarks, often contrasted with dead reckoning.

Synonyms

• Navigation meaning: Deduced reckoning, DR, estimated position.
• Estimate meaning: Guess, conjecture, rough estimate, speculation, ballpark figure.

Related Phrases

• To reckon without: To fail to consider a factor (idiomatically related through the verb "to reckon").
  • They had reckoned without the possibility of bad weather.
• Dead in the water: An idiom meaning completely stalled or unable to proceed (not directly related but shares the word "dead").
  • Without the new data, the research project is dead in the water.

Related Idioms

• A shot in the dark: A wild guess, very similar to the "estimate" meaning of dead reckoning.
  • His answer was a complete shot in the dark, pure dead reckoning.

Noun

1. navigation without the aid of celestial observations
2. an estimate based on little or no information