nonuplet
/ˈnɒnjʊplɪt/ /nɒnˈjuːplɪt/noun
1 Music. A group of nine notes to be performed in the time of eight or six. rare.
2Each of nine siblings resulting from a single pregnancy. Usually in plural.
3 Science. A multiplet of nine subatomic particles; an aggregate of nine components. rare.
Origin
Late 19th century; earliest use found in John Stainer (1840–1901), musicologist and composer. From classical Latin nōnus ninth + -plet.