orchid tree vs mountain ebony

orchid tree and mountain ebony both are nouns.

Word	Noun	Adjective	Verb	Adverb
orchid tree	Yes	No	No	No
mountain ebony	Yes	No	No	No

As nouns, orchid tree and mountain ebony are synonyms defined as:

orchid tree and mountain ebony: small East Indian tree having orchid-like flowers and hard dark wood

Other synonyms of orchid tree include Bauhinia variegata.

orchid tree (noun)	mountain ebony (noun)
small East Indian tree having orchid-like flowers and hard dark wood	small East Indian tree having orchid-like flowers and hard dark wood