Sound reflection is the process of sound waves bouncing off a surface and returning to the source. The three crossword solutions for the term 'sound reflection' are ECHO (4 letters), echoism (7 letters), and REVERBERATION (13 letters). ECHO is the most basic form of sound reflection, where a sound wave is reflected off a surface and returns to the source. Echoism is a more specific type of sound reflection, where the sound wave is reflected multiple times off a surface before returning to the source. REVERBERATION is the most complex form of sound reflection, where the sound wave is reflected multiple times off multiple surfaces before returning to the source.