Noun
The empty space in the center of a donut.
(US, Canada) A small ball-shaped pastry, made in the same manner as a donut, roughly the size of the hole in a donut.
These donut holes are delicious!
(US, insurance, welfare, slang) An income bracket where one is without benefits, even though benefits are available in the next lower and next higher brackets.
A section of water for which no one has fishing rights that is completely surrounded by regions where various parties hold fishing rights.
Source: en.wiktionary.org