1. A soft, smooth, and warm sound that is pleasing to the ear; lacking harshness or stridency
The mellow sound of the violin filled the concert hall.
O som suave do violino preencheu a sala de concertos.
2. An acoustic quality that is rich, mature, and fully developed, often associated with aged instruments or experienced musicians
The guitarist's mellow sound came from years of practice.
O som suave do guitarrista resultou de anos de prática.