nectar vs fruit juice

nectar and fruit juice both are nouns.

Word	Noun	Adjective	Verb	Adverb
nectar	Yes	No	No	No
fruit juice	Yes	No	No	No

As nouns, fruit juice is a hypernym of nectar; that is, fruit juice is a word with a broader meaning than nectar:

Other hypernyms of nectar include fruit crush.

nectar (noun)	fruit juice (noun)
(classical mythology) the food and drink of the gods; mortals who ate it became immortal	drink produced by squeezing or crushing fruit
fruit juice especially when undiluted
a sweet liquid secretion that is attractive to pollinators