Harmonious sounds can be described as a pleasing combination of musical notes or tones that create a pleasant and balanced auditory experience. The two crossword solutions for this term are 'EUPHONY' (7 letters) and 'MUSIC' (5 letters). EUPHONY is a term used to describe the pleasing sound of words or MUSIC, while MUSIC is an art form consisting of sound and silence expressed through time. Both terms are related to harmonious sounds, as they both involve the combination of musical notes or tones to create a pleasing auditory experience.