citron tree vs citron

citron tree and citron both are nouns.

Word	Noun	Adjective	Verb	Adverb
citron tree	Yes	No	No	No
citron	Yes	No	No	No

As nouns, citron tree and citron are synonyms defined as:

citron tree and citron: thorny evergreen small tree or shrub of India widely cultivated for its large lemonlike fruits that have thick warty rind

Other synonyms of citron tree include Citrus medica.

citron tree (noun)	citron (noun)
thorny evergreen small tree or shrub of India widely cultivated for its large lemonlike fruits that have thick warty rind	large lemonlike fruit with thick aromatic rind; usually preserved
	thorny evergreen small tree or shrub of India widely cultivated for its large lemonlike fruits that have thick warty rind