jelly vs grape jelly

jelly and grape jelly both are nouns.

Word	Noun	Adjective	Verb	Adverb
jelly	Yes	No	Yes	No
grape jelly	Yes	No	No	No

As nouns, grape jelly is a hyponym of jelly; that is, grape jelly is a word with a more specific, narrower meaning than jelly:

Other hyponyms of jelly include apple jelly.

jelly (noun)	grape jelly (noun)
a preserve made of the jelled juice of fruit	jelly made from grape juice
an edible jelly (sweet or pungent) made with gelatin and used as a dessert or salad base or a coating for foods
any substance having the consistency of jelly or gelatin

jelly (verb)	grape jelly (verb)
make into jelly