cinnamon bun vs cinnamon roll

cinnamon bun and cinnamon roll both are nouns.

Word	Noun	Adjective	Verb	Adverb
cinnamon bun	Yes	No	No	No
cinnamon roll	Yes	No	No	No

As nouns, cinnamon bun and cinnamon roll are synonyms defined as:

cinnamon bun and cinnamon roll: rolled dough spread with cinnamon and sugar (and raisins) then sliced before baking

Other synonyms of cinnamon bun include cinnamon snail.

cinnamon bun (noun)	cinnamon roll (noun)
rolled dough spread with cinnamon and sugar (and raisins) then sliced before baking	rolled dough spread with cinnamon and sugar (and raisins) then sliced before baking