Euchologion
Euchologion , noun
[New Latin euchologion, Greek {not transcribed} prayer book; {not transcribed} prayer, vow (from {not transcribed} to pray) + {not transcribed} to say, speak.]
(Ecclesiastical) A formulary of prayers; the book of offices in the Greek Church, containing the liturgy, sacraments, and forms of prayers.
Also: Euchology