Fraxinus nigra vs brown ash

Fraxinus nigra and brown ash both are nouns.

Word	Noun	Adjective	Verb	Adverb
Fraxinus nigra	Yes	No	No	No
brown ash	Yes	No	No	No

As nouns, Fraxinus nigra and brown ash are synonyms defined as:

Fraxinus nigra and brown ash: vigorous spreading North American tree having dark brown heavy wood; leaves turn gold in autumn

Other synonyms of Fraxinus nigra include basket ash, black ash, hoop ash.

Fraxinus nigra (noun)	brown ash (noun)
vigorous spreading North American tree having dark brown heavy wood; leaves turn gold in autumn	vigorous spreading North American tree having dark brown heavy wood; leaves turn gold in autumn