armed forces vs echelon

armed forces and echelon both are nouns.

Word	Noun	Adjective	Verb	Adverb
armed forces	Yes	No	No	No
echelon	Yes	No	No	No

armed forces (noun)	echelon (noun)
the military forces of a nation	a diffraction grating consisting of a pile of plates of equal thickness arranged stepwise with a constant offset
	a body of troops arranged in a line
	status in a society or organization