Definition of dead reckoning
1 : the determination without the aid of celestial observations of the position of a ship or aircraft from the record of the courses sailed or flown, the distance made, and the known or estimated drift
2 : guesswork
First Known Use of dead reckoning
Learn More about dead reckoning
Britannica.com: Encyclopedia article about dead reckoning
Seen and Heard
What made you want to look up dead reckoning? Please tell us where you read or heard it (including the quote, if possible).