MELODIOUSLY is an adverb that describes a sound or music being played in a pleasant and harmonious manner. ARIOSO, which has 6 letters, is an Italian musical term meaning 'in a singing style'. SWEETLY, which has 7 letters, is an adverb that describes something being done in a gentle, pleasing, and kind way. MELODICALLY, which has 11 letters, is an adverb that describes a sound or music being played in a melodic and harmonious manner. All of these terms can be used to describe the same concept: a sound or music being played in a pleasant and harmonious manner.