army corps vs corps

army corps and corps both are nouns.

Word	Noun	Adjective	Verb	Adverb
army corps	Yes	No	No	No
corps	Yes	No	No	No

As nouns, army corps and corps are synonyms defined as:

army corps and corps: an army unit usually consisting of two or more divisions and their support

army corps (noun)	corps (noun)
an army unit usually consisting of two or more divisions and their support	an army unit usually consisting of two or more divisions and their support
	a body of people associated together