Concept
Ennead

Overview
The Ennead or Great Ennead was a group of nine deities in Egyptian mythology worshipped at Heliopolis: the sun god Atum; his children Shu and Tefnut; their children Geb and Nut; and their children Osiris, Isis, Set, and Nephthys. The Ennead sometimes includes Horus the Elder; an ancient form of the falcon god, not the son of Osiris and Isis.
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
Possible passages
Found by search and not yet checked by a person; they may only mention the idea in passing.
We have gathered the Fourth and Fifth Ennead into a single volume. Of the Sixth Ennead, we have formed a separate volume, so that all the writings of Plotinos might be divided into three parts, of which the first contains three Enneads, the second two; and the third, a single Ennead. Here are the books that belong to the Sixth Ennead, and to the Third Volume. 1. Of the Kinds of Existence, the First, 42. 2. Of the…
Plotinus, Plotinos
The chapter “XXIV. CONTENTS OF THE VARIOUS ENNEADS.” is titled for Ennead; names Ennead several times.
In Egypt an ox is even worshipped as a deity; they call it Apis. It is distinguished by a conspicuous white spot on the right side, in the form of a crescent.
the Elder Pliny, The Boys' and Girls' Pliny
States what Ennead is.
In the second and third place, they thus distinguished the deities into those which are beneficial and those that are injurious to mankind. Those which are beneficial they call Jupiter, Juno, Mercury, Ceres; those who are mischievous the Dirae, Furies, and Mars.
Plutarch, Complete Works of Plutarch — Volume 3
States what Ennead is.
Related ideas
Opposing perspectives
Place in the tradition
Part of Gnosticism.