(music) Of, relating to, or being a melisma; the style of singing several notes to one syllable of text.
1998, Barbara Newman, Introduction, Barbara Newman (translator), Hildegard von Bingen, Symphonia: A Critical Edition of the Symphonia armonie celestium revelationum, Cornell University Press, 2nd Edition, page 28,
In general, the more melismatic a piece, the more solemn, elaborate, and difficult it is, and the more the text is dominated by the music.