Sound reflection refers to the bouncing back of sound waves when they hit a surface. Some synonyms for sound reflection include echo, reverberation, resonance, reflection, and acoustics. An echo is a direct repetition of a sound heard after an original sound wave has reflected off a surface. Reverberation is the persistence of sound in a space after the original sound has stopped due to multiple reflections off different surfaces. Resonance is when a sound wave vibrates at the same frequency as a resonating object, producing a louder and more sustained sound. Reflection is the redirection of sound waves when they encounter a boundary, and acoustics is the study of sound waves in a given space.