Defense Department vs Defense

Defense Department and Defense both are nouns.

Word	Noun	Adjective	Verb	Adverb
Defense Department	Yes	No	No	No
Defense	Yes	No	No	No

As nouns, Defense Department and Defense are synonyms defined as:

Defense Department and Defense: the federal department responsible for safeguarding national security of the United States; created in 1947

Other synonyms of Defense Department include Department of Defense, DoD, United States Department of Defense.

Defense Department (noun)	Defense (noun)
the federal department responsible for safeguarding national security of the United States; created in 1947	the federal department responsible for safeguarding national security of the United States; created in 1947