Lewis Short
(adjective) : sesquĭ-octāvus, a, um, , corresp. to the Gr. ἐπόγδοος
* Containing nine eighths, or one and an eighth; bearing the ratio of nine to eight: intervallum,Cic. Univ. 7, 21; cf. sesquitertius, and v. sesqui.
Charlton T. Lewis, Charles Short, A Latin Dictionary