The Collaborative International Dictionary of English v.0.48:

Menaion \Me*na"ion\ (m[-e]*n[=a]"y[o^]n), n.; pl. Menaia
   (-y[.a]). [NL., from Gr. mhnai^os 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.
   [1913 Webster] Menild