arboretum vs botanical garden

arboretum and botanical garden both are nouns.

Word	Noun	Adjective	Verb	Adverb
arboretum	Yes	No	No	No
botanical garden	Yes	No	No	No

As nouns, arboretum and botanical garden are synonyms defined as:

arboretum and botanical garden: a facility where trees and shrubs are cultivated for exhibition

arboretum (noun)	botanical garden (noun)
a facility where trees and shrubs are cultivated for exhibition	a facility where trees and shrubs are cultivated for exhibition