Webster's Revised Unabridged Dictionary · 1913

Alleluia

Alleluia ({not transcribed}) , noun

[Latin alleluia, Greek {not transcribed}, from Hebrew hallēlū-yāh. See Hallelujah.]

An exclamation signifying Praise ye Jehovah. Hence: A song of praise to God. See Hallelujah, the commoner form.
I heard a great voice of much people in heaven, saying, Alleluia. — Rev. xix. 1

Also: Alleluiah