ennead

From Ancient Greek ἐννεάς (enneás), ἐννεάδος (enneádos, “body of nine”) +‎ -ad (suffix designating a unit); analysable as ennea- +‎ -ad. The Greek words ἐννεάς and ἐννεάδος are derived from ἐννέᾰ (ennéă, “nine”) (ultimately from Proto-Indo-European *h₁néwn̥ (“nine”)) + -ᾰ́ς (-ắs, suffix forming abstract nouns of number from numerals) or -ος (-os).