U. S. Army vs military machine

U. S. Army and military machine both are nouns.

Word	Noun	Adjective	Verb	Adverb
U. S. Army	Yes	No	No	No
military machine	Yes	No	No	No

U. S. Army (noun)	military machine (noun)
the army of the United States of America; the agency that organizes and trains soldiers for land warfare	the military forces of a nation