mellifluous

An mellifluous sound is pleasant and smooth, like music or honey.

When we talk about sounds being mellifluous, it usually means they're easy to listen to and enjoyable. Think of a gentle stream babbling over rocks or the soft hum of a harp string. Poets often use this word when describing the tone of someone's voice – "her voice was mellifluous as she read the poem aloud" might mean that her voice was rich, soothing, and pleasant to hear. In music, composers try to create melodies with a mellifluous quality so they're calming and beautiful.