noun, noun or participle which takes 'suru', intransitive verb
Physical echo of sound; also used for the reverberation of a voice or noise in a space.
山に向かって叫ぶと、大きな反響が返ってきた。
When I shouted toward the mountain, a loud echo came back.
The reverberation in the hall is too strong, making it hard to hear the speech.
noun
response; reaction; repercussions
Figurative use: the response or impact that an action, statement, or event has on society, a group, or an individual.
彼の発言は大きな反響を呼んだ。
His remarks caused a huge reaction.
新製品の発表は業界に反響を与えた。
The announcement of the new product had an impact on the industry.