1. the quality of being sweet or musical in sound; smoothness and sweetness of tone or voice
Usage: formal; often used to describe voices, music, or language
2. the quality of being pleasant, smooth, or agreeable in manner or expression
Usage: formal; often used figuratively

Examples

• The singer's mellifluousness captivated the entire audience.
• Her voice had a natural mellifluousness that made even simple words sound beautiful.
• The mellifluousness of the violin solo brought tears to many listeners' eyes.
• He spoke with such mellifluousness that people were drawn to his words.
• The poet's mellifluousness was evident in every carefully chosen phrase.
• The orchestra's mellifluousness created a sense of calm and wonder in the concert hall.