Pannychis (Gk. παννυχίς, literally: ‘all-night [service]’),
a Greek word for a Vigil (q.v.), more usually known as ἀγρυπνία. It occurs already in St Athanasius (Apol. ad Const. 25). The term ‘Pannychis’ came to be used mainly for vigils for the dead, hence the Slavonic word Panikhida, meaning a memorial service for the dead (which takes the form of a drastically curtailed vigil).