Source : Webster's Revised Unabridged Dictionary (1913)

Menaion \Me*na"ion\, n.; pl. {Menaia} (-y[*a]). [NL., from Gr. ?
   monthly.] (Eccl.)
   A work of twelve volumes, each containing the offices in the
   Greek Church for a month; also, each volume of the same.
   --Shipley.