Definitions for "Trisagion"
Keywords:  thrice, immortal, hymn, mighty, liturgy
The Thrice Holy (HOLY God, HOLY Mighty, HOLY Immortal...) Prayers are chanted before the Prokimen and Epistle Reading. The Thrice Holy Prayers are also part of the usual begining of all our Orthodox prayers.
a short hymn consisting of the words 'Holy God, Holy and Strong, Holy and Immortal', sung three or more times
(Gr., "thrice-holy"): liturgical invocation: "Holy God, holy and strong, holy and immortal, have mercy on us."
An ancient anthem, -- usually known by its Latin name tersanctus.See Tersanctus.