Which term describes a sound that flows smoothly and sweetly?

The term that describes a sound that flows smoothly and sweetly is "mellifluous." This word derives from the Latin "mel," meaning honey, which conveys a sense of sweetness and pleasantness. When a sound is mellifluous, it has a rich, harmonious quality that is delightful to hear, often associated with music or a soft, soothing voice. This term effectively captures the essence of a sound that is both melodious and appealing, making it an ideal choice to describe a sound that flows smoothly and sweetly.

The other terms refer to sounds with negative or unpleasant qualities. For example, raucous denotes harshness and loudness, while harsh describes rough and grating sounds, and scratchy refers to sounds that are rough or irritating to the ears. In contrast, mellifluous stands out as the only term that encompasses a sense of beauty and fluidity in sound.