sugar loaf vs loaf sugar

sugar loaf and loaf sugar both are nouns.

Word	Noun	Adjective	Verb	Adverb
sugar loaf	Yes	No	No	No
loaf sugar	Yes	No	No	No

As nouns, sugar loaf and loaf sugar are synonyms defined as:

sugar loaf and loaf sugar: a large conical loaf of concentrated refined sugar

Other synonyms of sugar loaf include sugarloaf.

sugar loaf (noun)	loaf sugar (noun)
a large conical loaf of concentrated refined sugar	a large conical loaf of concentrated refined sugar