analog vs echo

analog and echo both are nouns.

Word	Noun	Adjective	Verb	Adverb
analog	Yes	Yes	No	No
echo	Yes	No	Yes	No

As nouns, echo is a hyponym of analog; that is, echo is a word with a more specific, narrower meaning than analog:

analog (noun)	echo (noun)
something having the property of being analogous to something else	an imitation or repetition
	the repetition of a sound resulting from reflection of the sound waves
	a reflected television or radio or radar beam
	a close parallel of a feeling, idea, style, etc.
	a reply that repeats what has just been said

analog (adjective)	echo (adjective)
of a circuit or device having an output that is proportional to the input