[L. ter thrice + sanctus holy.] See quots., and SANCTUS, TRISAGION.
1832. W. Palmer, Orig. Liturg., I. 39. After this follows the hymn Tersanctus.
1842. Hook, Ch. Dict., Tersanctus, the Latin title of the hymn in the Liturgy beginning ‘With Angels and Archangels,’ &c. … In the Liturgy of Milan it has been used from time immemorial, under the name of Trisagium.
1892. C. Whitaker, Stud. Aid Prayer Bk., 81. The Triumphal or Seraphic Hymn. This hymn is sometimes called Ter-Sanctus (Thrice holy). It is indeed a Biblical Ter-Sanctus, but it is not the ‘Liturgical Trisagion.’
