ennead

Etymology

Comes from Ancient Greek ἐννεάς (enneás), ἐννεάδος (enneádos, "body of nine"), combined with -ad (a suffix designating a unit); it can also be analysed as ennea- + -ad. These Greek words ἐννεάς and ἐννεάδος themselves derive from ἐννέᾰ (ennéă, "nine") — ultimately from Proto-Indo-European *h₁néwn̥ ("nine") — plus the suffix -ᾰ́ς (-ắs, forming abstract nouns of number from numerals) or -ος (-os).