Praise ye Jehovah, frequently rendered "Praise ye the LORD," stands at the beginning of ten of the psalms (106, 111-113, 135, 146-150), hence called "hallelujah psalms." From its frequent occurrence it grew into a formula of praise. The Greek form of the word (alleluia) is found in Revelation 19:1, 3, 4, 6.

Noah Webster's New International Dictionary of the English Language

(n. & interj.) 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.