Singing a single syllable while changing over notes in succession.
From the Hellenistic Greek melisma, 'song', 'air' or 'melody', which comes from the ancient Greek, melos, 'song', and isma, '-ism'.
Beyonce is well known for her use of melisma in her music.
A classic example of melisma is in the well-known carol Gloria. Mariah Carey is also known for her use of melisma. Some people find melisma to be indicative of a singer's ability while others find it detracts from a song.