doughnut machine vs donut machine

doughnut machine and donut machine both are nouns.

Word	Noun	Adjective	Verb	Adverb
doughnut machine	Yes	No	No	No
donut machine	Yes	No	No	No

As nouns, doughnut machine and donut machine are synonyms defined as:

doughnut machine and donut machine: a machine used to fry large quantities of doughnuts at once.

Other synonyms of doughnut machine include donut fryer, doughnut fryer.

doughnut machine (noun)	donut machine (noun)
a machine used to fry large quantities of doughnuts at once.	a machine used to fry large quantities of doughnuts at once.