State Department vs DoS

State Department and DoS both are nouns.

Word	Noun	Adjective	Verb	Adverb
State Department	Yes	No	No	No
DoS	Yes	No	No	No

As nouns, State Department and DoS are synonyms defined as:

State Department and DoS: the federal department in the United States that sets and maintains foreign policies

Other synonyms of State Department include Department of State, State, United States Department of State.

State Department (noun)	DoS (noun)
the federal department in the United States that sets and maintains foreign policies	the federal department in the United States that sets and maintains foreign policies
a department of government in one of the 50 states