Defense Information Systems Agency vs Defense Department

Defense Information Systems Agency and Defense Department both are nouns.

Word	Noun	Adjective	Verb	Adverb
Defense Information Systems Agency	Yes	No	No	No
Defense Department	Yes	No	No	No

Defense Information Systems Agency (noun)	Defense Department (noun)
a combat support agency in the Department of Defense responsible for developing and operating and supporting information systems to serve the needs of the President and the Secretary of Defense and the Joint Chiefs of Staff	the federal department responsible for safeguarding national security of the United States; created in 1947