In Formula 1, DNF stands for "Did Not Finish". It is an abbreviation used to denote when a driver fails to complete the race due to various reasons such as a crash or a technical problem with the car. The term is also used in other racing disciplines to indicate a participant who does not finish a given race, either because of a mechanical failure, injury, or involvement in an accident. In contrast, DNS stands for "Did Not Start," which means that the driver was qualified for the race but did not start due to various reasons such as technical problems during the warm-up lap.