[Sanc.tus] n [ME, fr. LL Sanctus, sanctus, sanctus Holy, holy, holy, opening of a hymn sung by the angels in Isa 6:3] (15c): an ancient Christian hymn of adoration sung or said immediately before the prayer of consecration in traditional liturgies
SANCTUS
Meaning of SANCTUS in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012