The Collaborative International Dictionary of English v.0.48:

Halleluiah \Hal`le*lu"iah\, Hallelujah \Hal`le*lu"jah\
   (h[a^]l`l[-e]*l[=u]"y[.a]), n. & interj. [Heb. See
   Alleluia.]
   Praise ye Jehovah; praise ye the Lord; -- an exclamation used
   chiefly in songs of praise or thanksgiving to God, and as an
   expression of gratitude or adoration. --Rev. xix. 1 (Rev.
   Ver. )
   [1913 Webster]

         So sung they, and the empyrean rung
         With Hallelujahs.                        --Milton.
   [1913 Webster]

         In those days, as St. Jerome tells us,"any one as he
         walked in the fields, might hear the plowman at his
         hallelujahs."                            --Sharp.
   [1913 Webster]