boardroom vs diwan

boardroom and diwan both are nouns.

Word	Noun	Adjective	Verb	Adverb
boardroom	Yes	No	No	No
diwan	Yes	No	No	No

As nouns, diwan is a hyponym of boardroom; that is, diwan is a word with a more specific, narrower meaning than boardroom:

boardroom: a room where a committee meets (such as the board of directors of a company)
diwan: a Muslim council chamber or law court

Other hyponyms of boardroom include divan.

boardroom (noun)	diwan (noun)
a room where a committee meets (such as the board of directors of a company)	a Muslim council chamber or law court
	a collection of Persian or Arabic poems (usually by one author)
	a Muslim council of state