citron vs Buddha's hand

citron and Buddha's hand both are nouns.

Word	Noun	Adjective	Verb	Adverb
citron	Yes	No	No	No
Buddha's hand	Yes	No	No	No

As nouns, Buddha's hand is a hyponym of citron; that is, Buddha's hand is a word with a more specific, narrower meaning than citron:

citron: large lemonlike fruit with thick aromatic rind; usually preserved
Buddha's hand: large lemonlike fruit segmented into finger-like sections; most varieties contain no pulp or juice.

citron (noun)	Buddha's hand (noun)
large lemonlike fruit with thick aromatic rind; usually preserved	large lemonlike fruit segmented into finger-like sections; most varieties contain no pulp or juice.
thorny evergreen small tree or shrub of India widely cultivated for its large lemonlike fruits that have thick warty rind