2Nautical a course navigated in fog or similar conditions, in which the speed and the time spent travelling in a known direction from a known position, rather than direct observation, are used to calculate position (now rare).
Origin
Mid 19th century.
Definition of time course in US English:
time course
noun
1The course followed by something over time.
2Nautical a course navigated in fog or similar conditions, in which the speed and the time spent travelling in a known direction from a known position, rather than direct observation, are used to calculate position (now rare).