dough·nut also do·nut 
(dōnŭt′, -nət)
(dōnŭt′, -nət)n.
1. A small ring-shaped cake made of rich, light dough that is fried in deep fat.
2. Something whose form is reminiscent of a ring-shaped cake.
3. A fast, tight 360° turn made in a motor vehicle or motorized boat.
[DOUGH + earlier nut, a small rounded cake or cookie; see NUT.]