echo vs reply

echo and reply both are nouns.

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

As nouns, reply is a hypernym of echo; that is, reply is a word with a broader meaning than echo:

Other hypernyms of echo include response.

echo (noun)	reply (noun)
an imitation or repetition	the speech act of continuing a conversational exchange
the repetition of a sound resulting from reflection of the sound waves	a statement (either spoken or written) that is made to reply to a question or request or criticism or accusation
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