doughnut machine vs fryer

doughnut machine and fryer both are nouns.

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

As nouns, fryer is a hypernym of doughnut machine; that is, fryer is a word with a broader meaning than doughnut machine:

doughnut machine: a machine used to fry large quantities of doughnuts at once.
fryer: A kitchen appliance for deep frying; its size depends on intended use.

Other hypernyms of doughnut machine include machine, deep fat fryer, deep fryer, frier, fryolator.

doughnut machine (noun)	fryer (noun)
a machine used to fry large quantities of doughnuts at once.	A kitchen appliance for deep frying; its size depends on intended use.
	flesh of a medium-sized young chicken suitable for frying