PANNYCHIS. - In the Byzantine rite, this word can designate several liturgical Offices.
1) Today among the Greeks, the p. is the divine Office that lasts all night and thus corresponds to the Latin Vigils. This Office is celebrated in monasteries, especially on Mount Athos, 30 to 50 times a year, on the night preceding major feasts; it begins around 8 or 9 p.m. with the Great Vespers, to which are added the orthros (= Matins and Lauds) with the Hours of Prime, Terce, Sext, so that by 9 or 10 a.m. the Eucharistic Liturgy will conclude. In parishes, however, the p. is generally celebrated on Saturday evenings in an abbreviated ceremony (Vespers, orthros and Prime) partly read and not sung.
2) The Slavs give the Office described above the name stesnosko Bideine (= all-night vigil) and reserve the term p. for the Office of the Dead, which, however, follows substantially the structure of the orthros.
3) In antiquity, as is evident from Greek manuscripts, there existed an Office called p. which was added to Vespers, or preceded the orthros, or was included in the composition of the apodeipnon; it comprised Psalm 50, one or two canons of supplication, and the Great Doxology (cf. A. Dmitrievskij, Opisanie... I. Kiev 1895, pp. 604 and 607).