The term 'SWEET SOUND' can be broken down into two crossword solutions: COO and MUSIC. COO is a three-letter word that is an onomatopoeia for the sound made by a dove or pigeon. MUSIC is a five-letter word that refers to the art of arranging sounds in time to create a composition that is often pleasing to the ear. Together, these two words form the phrase 'SWEET SOUND, ' which can be interpreted as a description of a pleasant sound.