The first part of Hallelujah, Halal (Strong's Concordance #H1984), means "to shine or praise." The "jah" or second part of the word is derived from either a shorten version of one of God's names (Jah, (some believe "yah"), Strong's #H3050) or a full version (Jehovah, Strong's #H3068).
The words that comprise Hallelujah as a distinct praise of God, which in English is usually translated as "Praise ye the Lord" or simply "Praise the Lord," are found together only in the book of Psalms.
Hallelujah is found in Psalms 104 - 106, 111 - 113, 115 - 117, 135, 146 - 150, or fifteen distinct Psalms for a total number of twenty-six occurrences. This praise occurs once in seven Psalms, twice in five, and three times in three others (135, 146 and 148). Psalm 104 - 106 was written by priests serving during King David's reign while the remaining ones were penned by David himself from 1010 to 970 B.C.
Psalms 146 uses the shortened "jah" for God's name to form Hallelujah in its first and tenth verse, but also uses the full Hebrew word Jehovah as the basis of "jah" in its first verse. Two versions of God's name are also used in Psalm 148.
Praise ye the Lord (Jah). Praise the Lord (Jehovah), O my soul (Psalm 146:1, KJV).
Praise ye the Lord (Jah). Praise ye the Lord (Jehovah) from the heavens: praise him in the heights (Psalm 148:1, KJV).
According to the 1906 Jewish Encyclopedia, a group of eighteen Psalms, labeled the Hallelujah Psalms, was sung as hymns in the service of Jerusalem's temple. They were especially used in celebration of God's annual Feast days. Additionally, they were sung in synagogues and private gatherings. This group was composed of Psalms 105 - 107, 111 - 118, 135 - 136 and 146 - 150.
Alleluia in the New Testament
In the KJV New Testament, the word Alleluia (Strong's #G239), found only in Revelation (Revelation 19:1, 3, 4, 6), is the Greek form of Hallelujah. The word means, "praise ye Jah."
And after these things I heard a great voice of much people in heaven, saying, Alleluia; Salvation, and glory, and honor, and power, unto the Lord our God . . .
And again they said, Alleluia. And her smoke rose up for ever and ever. And the four and twenty elders and the four beasts fell down and worshipped God that sat on the throne, saying, Amen; Alleluia . . .
And I heard as it were the voice of a great multitude, and as the voice of many waters, and as the voice of mighty thunderings, saying, Alleluia (praise ye Jah!): for the Lord God omnipotent reigneth (Revelation 19:1, 3 - 4, 6, KJV).
The word Hallelujah (or Alleluia), although used in the Psalms and Revelation, seems to have experienced significantly less use in more modern songs sung at church services.