Defense vs executive department

Defense and executive department both are nouns.

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

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

Defense: the federal department responsible for safeguarding national security of the United States; created in 1947
executive department: a federal department in the executive branch of the government of the United States

Defense (noun)	executive department (noun)
the federal department responsible for safeguarding national security of the United States; created in 1947	a federal department in the executive branch of the government of the United States