citron vs citron tree

citron and citron tree both are nouns.

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

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

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

Other synonyms of citron include Citrus medica.

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