For the Earth food, please see doughnut.
A donut was a maneuver that involved driving a vehicle in a circle. The maneuver could also be done by starships in spaceflight, by way of a sustained circular drift.
In 2257, Keyla Detmer performed such a maneuver with the USS Discovery over the planet Terralysium, allowing the gravitational effect of a dark matter asteroid to capture radioactive debris from Terralysium's ring system, preventing it from colliding with the surface. (DIS: "New Eden")