grape sugar vs glucose

grape sugar and glucose both are nouns.

Word	Noun	Adjective	Verb	Adverb
grape sugar	Yes	No	No	No
glucose	Yes	No	No	No

As nouns, glucose is a hypernym of grape sugar; that is, glucose is a word with a broader meaning than grape sugar:

grape sugar: an isomer of glucose that is found in honey and sweet fruits
glucose: a monosaccharide sugar that has several forms; an important source of physiological energy

grape sugar (noun)	glucose (noun)
an isomer of glucose that is found in honey and sweet fruits	a monosaccharide sugar that has several forms; an important source of physiological energy