Ennead

The ennead, according to the Pythagoreans, circulates all numbers within itself, and there can be no number beyond it. For the natural progression of numbers is as far as to 9, but after it their retrogression takes place. For 10 becomes as it were again the monad. […] Hence it is not possible there should be any elementary number beyond the ennead.

Source: wiktionary

[T]he ennead is subtracted for this cause, because the three hundred and sixty parts of the entire [circle] consist of enneads, and for this reason the four regions of the world are circumscribed by ninety perfect parts.

Source: wiktionary

We may assert with confidence that no cycle of this kind, and of equal antiquity or even of inferior antiquity, is the actual existence better attested or more thoroughly authenticated than that of this octaëteris of Philammon of Delphi, or, as we may truly call it, this original Pythian ennead of primitive Hellas.

Source: wiktionary

The exquisite language of the prophecy of Isaiah, especially in its last three enneads, may have had a nearer primary reference to, and a nearer fulfilment in, the return of the exiles under Zerubbabel, and Ezra, and Nehemiah; […]

Source: wiktionary