Navigation without the aid of celestial observations WordNet 3.0 & Open English WordNet

In navigation, dead reckoning is the process of calculating the current position of a moving object by using a previously determined position, or fix, and incorporating estimates of speed, heading, and elapsed time. Wikipedia

Process for estimating the value of a variable quantity by using a previous value and adding any changes. Wikipedia Disambiguation

Means of calculating position Wikidata

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. Wiktionary

Method of estimating the position of a ship or aircraft. Wiktionary (translation)