SANCTUS
Sanc"tus, n. Etym: [L. sanctus, p.p. of sancire.]
1. (Eccl.)
Definition: A part of the Mass, or, in Protestant churches, a part of the
communion service, of which the first words in Latin are Sanctus,
sanctus, sanctus [Holy, holy, holy]; -- called also Tersanctus.
2. (Mus.)
Definition: An anthem composed for these words. Sanctus bell, a small bell
usually suspended in a bell cot at the apex of the nave roof, over
the chancel arch, in mediæval churches, but a hand bell is now often
used; -- so called because rung at the singing of the sanctus, at the
conclusion of the ordinary of the Mass, and again at the elevation of
the host. Called also Mass bell, sacring bell, saints' bell, sance-
bell, sancte bell.
Source: Webster’s Unabridged Dictionary 1913 Edition