The Sanctus (Latin: Sanctus, "Holy") is a hymn in Christian liturgy. It may also be called the epinikios hymnos (Greek: ἐπινίκιος ὕμνος, "Hymn of Victory") when referring to the Greek rendition and parts of it are sometimes called "Benedictus". Tersanctus (Latin: "Thrice Holy") is another, rarer name for the Sanctus. The same name is sometimes used for the Trisagion.
In Western Christianity, the Sanctus forms part of the Ordinary and is sung (or said) as the final words of the Preface of the Eucharistic Prayer of remembrance, consecration, and praise. The preface, which alters according to the season, usually concludes with words describing the praise of the worshippers joining with the angels, who are pictured as praising God with the words of the Sanctus. In the Byzantine Rite and general Eastern Orthodox Christianity, the Sanctus is offered as a response by the choir during the Holy Anaphora.