Question

give the meaning of the term echo. why do we not hear echo in our ordinary surroundings?​

Answer 1

this is because our sound waves get reflected from the walls of the hug back to us. the reflected sound out here is called an echo. and an echo is defined. as the repetition of sound caused by the reflection of sound waves from a hard surface back.

Answer 2

repetition of sound is called echo.
we do not hear echo in our ordinary surroundings because echo needs minimum 17m distance and no observing material such as solids.