[1] : The Collaborative International Dictionary of English v.0.48

doughnut \dough"nut\, n.
   a small cake usually sweetened fried in a kettle of boiling
   lard.
   1913 webster

[2] : WordNet (r) 2.0

doughnut
     n 1: a toroidal shape; "a ring of ships in the harbor"; "a halo
          of smoke" syn: ring, halo, annulus, anulus, anchor
          ring
     2: a small ring-shaped friedcake syn: donut, sinker
see also:
ring halo annulus anulus anchor ring donut 
sinker 

Doughnut >> D Words
Doughnut, definition of term: Doughnut
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