juice vs tomato juice

juice and tomato juice both are nouns.

Word	Noun	Adjective	Verb	Adverb
juice	Yes	No	No	No
tomato juice	Yes	No	No	No

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

juice: the liquid part that can be extracted from plant or animal tissue by squeezing or cooking
tomato juice: the juice of tomatoes (usually bottled or canned)

Other hyponyms of juice include gravy, pan gravy, lemon juice, lime juice, papaya juice, carrot juice, V-8 juice.

juice (noun)	tomato juice (noun)
any of several liquids of the body	the juice of tomatoes (usually bottled or canned)
the liquid part that can be extracted from plant or animal tissue by squeezing or cooking
electric current
energetic vitality