embassy vs diplomatic building

embassy and diplomatic building both are nouns.

Word	Noun	Adjective	Verb	Adverb
embassy	Yes	No	No	No
diplomatic building	Yes	No	No	No

As nouns, diplomatic building is a hypernym of embassy; that is, diplomatic building is a word with a broader meaning than embassy:

embassy (noun)	diplomatic building (noun)
a diplomatic building where ambassadors live or work	government building in which diplomats live or work
an ambassador and his entourage collectively