Lewis & Short

allēlūja, interj. [Heb. [??] = praise ye Jehovah] (the sec. syll. is short in Sid. Ep. 2, 10; Prud. Cath. 4, 72), Vulg. Psa. 104, 1; ib. Apoc. 19, 1 al.

hallĕlūjah (āllĕlūia), interj. [Hebr. halal, to praise; Jah = Jehovah], praised be God! praise the Lord! Form hall-, August. Ep. 86, 178; Sid. Ep. 2, 10; Prud. Nol. Carm. 37, 56. Form all-, Vulg. Job, 13, 22; Psa. 104, 1; Apoc. 19, 1, 3, 4 al.
Deriv. hallĕlūjătĭcus, a, um: psalmi, devoted to praise, containing hallelujahs, August. Psa. 105.