Vox Angelica refers to the voice of an angel, and there are various synonyms for it. The most widely used synonym is "angelic voice," which is often associated with high-pitched and smooth vocals. Other synonyms include "celestial voice," "heavenly voice," and "divine voice," which suggest the divine and supernatural quality of the voice. "Seraphic voice" and "cherubic voice" are also used as synonyms for Vox Angelica, as they refer to angelic beings in Christianity. Lastly, "ethereal voice" and "otherworldly voice" describe a voice that sounds as though it's coming from a different world, adding to the mystical and mysterious nature of the Vox Angelica.