echo- When a sound is produced inside a large hall or a similar structure, the sound bounces back from the walls of the structure. The sound reflected back from the walls is known as the echo of the sound.
> echo is usually clear and can be clearly distinguished.
reverberation- The phenomenon of reverberation is caused by overlapping of multiple echoes.
IN SIMPLE WORDS - Echo is a single reflection of a sound wave whereas reverberation is the superposition of multiple echoes.
> An echo is easily distinguishable and is almost as same as the original sound. The reverberation is not distinguishable and fades out in an exponential manner.
HOPE IT HELPED:)