early 12c., from Late Latin Te Deum laudamus "Thee God we praise," first words of the ancient Latin hymn.
A hymn of praise to God, containing many passages from the Bible, that is used in the Anglican Communion, the Lutheran Church, and the Roman Catholic Church as part of morning prayers on festive occasions. It begins, “Te Deum laudamus,” meaning, “We praise thee, O God.”
A hymn of praise to God, with words taken largely from the Bible, that is used by many groups of Christians. The “Te Deum” has been set to music by George Frederick Handel and by many other composers for performance in worship services of thanksgiving (after a victory in war, for example). The Latin words Te Deum laudamus mean “Thee, God, we praise.”