DoI vs executive department

DoI and executive department both are nouns.

Word	Noun	Adjective	Verb	Adverb
DoI	Yes	No	No	No
executive department	Yes	No	No	No

As nouns, executive department is a hypernym of DoI; that is, executive department is a word with a broader meaning than DoI:

DoI: the United States federal department charged with conservation and the development of natural resources; created in 1849
executive department: a federal department in the executive branch of the government of the United States

DoI (noun)	executive department (noun)
the United States federal department charged with conservation and the development of natural resources; created in 1849	a federal department in the executive branch of the government of the United States