PENTECOSTARION

ˌ ̷ ̷ ̷ ̷ˌkȯˈsta(a)rēˌän, -käˌ- noun

( -s )

Etymology: Late Greek pentēkostarion, from pentēkostē Pentecost

: a liturgical book in the Eastern Church containing offices for the period from Easter Sunday to the first Sunday after Pentecost