Jah or Yah (Hebrew: , Yah) is a short form of Yahweh (in consonantal spelling YHWH Hebrew: ?, called the tetragrammaton), the proper name of God in the Hebrew Bible. This short form of the name occurs 50 times in the text of the Hebrew Bible, of which 24 form part of the phrase "Hallelujah", which is actually a two-word phrase, not one word.
In an English-language context, the name Jah is now most commonly associated with the Rastafari. It is otherwise mostly limited to the phrase Hallelujah and theophoric names such as Elijah. "Jah" is an abbreviation of "Jehovah", the English transliteration of the Hebrew Tetragrammaton , God's name (Exodus 3:13). In the King James Version (1611) there is only a single instance of JAH (capitalised), in Psalm 68:4. An American Translation (1939) follows KJV in using Yah in this verse. The conventional English pronunciation of Jah is , even though the letter J here transliterates the palatal approximant (Hebrew ? Yodh). The spelling Yah is designed to make the pronunciation explicit in an English-language context (see also romanization of Hebrew).
On the assumption that a and e are the correct vowels, Yahweh is a name of God in the Hebrew language. Yahu is a well-attested short form of the full or extended name Yahweh. The short form Jah/Yah, which appears in Exodus 15:2 and 17:16, Psalm 89:9, Song of Songs 8:6, is preserved also in theophoric names such as Elijah ("my god is Jah"), Malchijah ("my king is Jah"), and (Adonijah) "my lord is Jah", etc. as well as in the phrase Hallelujah. The name "Joel" is derived from combining the word Jah with the word El.
Rastafari use the terms "Jah" or sometimes "Jah Jah" as a term for the Lord God of Israel and/or Haile Selassie, who some Rastafarians regard as the incarnation of The God of the Old Testament or as the reincarnation of Jesus Christ who is also known by the title Janhoy.
Yah occurs 50 times: 43 times in the Psalms, in Exodus 15:2; 17:16; Isaiah 12:2; 26:4, and twice in Isaiah 38:11.
At Revelation 19:1-6, Jah—a contraction of the name Yahweh—is embedded in the phrase "hallelujah" (Tiberian hall?lûy?h), a Hebrew expression that literally means "Praise Jah". The short form "IA" (Yah or Jah ()) in the phrase hallelouia () is transcribed by the Greek "Ia".
In the King James Version of the Christian Bible, the Hebrew  is transliterated as "JAH" (capitalised) in only one instance: "Sing unto God, sing praises to his name: extol him that rideth upon the heavens by his name JAH, and rejoice before him".An American Translation renders the Hebrew word as "Yah" in this verse. In the 1885 Revised Version and its annotated study edition, The Modern Reader's Bible, which uses the Revised Version as its base text, also transliterates "JAH" in Psalms 89:8 which reads,"O LORD God of hosts, who is a mighty one, like unto thee, O JAH? and thy faithfulness is round about thee".
With the rise of the Reformation, reconstructions of the Tetragrammaton became popular. The Tyndale Bible was the first English translation to use the anglicized reconstruction. The modern letter "J" settled on its current English pronunciation only around 500 years ago; in Ancient Hebrew, the first consonant of the Tetragrammaton always represents a "Y" sound.
Rotherham's Emphasised Bible includes 49 uses of Jah. In the Sacred Scriptures Bethel Edition Bible, the Jerusalem Bible, and the New Jerusalem Bible (prior to 1998) the name "YHWH" and its abbreviated form "Yah" is found. The New World Translation of the Holy Scriptures, used primarily by Jehovah's Witnesses, employs "Jah" in the Hebrew Scriptures, and translates Hallelujah as "Praise Jah" in the Greek Scriptures. The Divine Name King James Bible employs "JAH" in 50 instances within the Old Testament according to the Divine Name Concordance of the Divine Name King James Bible, Second Edition.
The Spanish language Reina Valera Bible employs "JAH" in 21 instances within the Old Testament according to the Nueva Concordancia Strong Exhaustiva. The Darby Bible, Young's Literal Translation, The Jubilee Bible 2000, Lexham English Bible, The Complete Jewish Bible, Names of God Bible, The Recovery Version, Green's Literal Translation, the New Jewish Publication Society or NJPS Tanakh and World English Bible includes "Jah" (Yah in the Lexham English Bible, Complete Jewish Bible, the NJPS Tanakh and the World English Bible) numerous times within the Old Testament (as well as in the New Testament or New Covenant as is the case in Christian and Messianic Jewish Bibles) as "Hallelujah!" or "Alleluia!" (Praise Jah or Yah in either instance) which is also employed throughout the Old Testament of these Bible versions.
"Hallelujah!" or "Alleluia!" is also used in other Bible versions such as the Divine Name King James Bible, American Standard Version, the Recovery Version, The Tree of Life Version, Amplified Bible, God's Word Translation, Holman Christian Standard Bible, International Standard Version, The Message, New American Bible Revised Edition, The Jerusalem Bible, The New Jerusalem Bible, NJPS Tanakh, The first JPS translation, The Living Bible, The Bible in Living English, Young's Literal Translation, King James Version, The Spanish language Reina Valera and even in Bible versions that otherwise do not generally use the Divine Name such as the New King James Version, English Standard Version, J.B. Phillips New Testament, New International Version, Douay-Rheims Version, God's Word Translation, Revised Standard Version, New Revised Standard Version, The Jubilee Bible 2000, New American Standard Bible, New Century Version, New International Reader's Version and several other versions, translations and/or editions in English and other languages varying from once to numerous times depending on the Bible version especially and most notably in Revelation Chapter 19 in Christian and Messianic Jewish Bibles.
For example, it is referenced in Bob Marley's "Is This Love", in the line: "We'll share the same room, for Jah provide the bread". It appears in the title of Third World's hit song "Try Jah Love". The Mighty Diamonds song "Pass the Koutchie" has the following lyric: "Cause the spirit of Jah, you know he leads you on". Similarly, Mystic Roots "Pass the Marijuana" contains the words "Pass the marijuana, give Jah thanks and praise today". Also Stevie Wonder's ode to Marley, "Master Blaster (Jammin')", contains the following verse lyric: "We've agreed to get together, joined as children in Jah". P.O.D.'s song "Strength of My Life" contains the words "If Jah is for me, tell me whom I gon' fear? (no I won't fear), and Jah of Jacob, deserving of my love". Also, Jah is referenced many times in Damian Marley's song "Road to Zion" and in the songs of Costa Rican singer Noah, such as "If you don't believe in Jah, we can not be together". Additionally, Jah has been linked to acid-reggae music. For example, the name can be heard in Thievery Corporation's song "The Outernationalist". Hardcore punk/reggae band Bad Brains' first album contains the songs "Jah Calling" and "I Luv I Jah". The use of Jah in music is also evident in the reggae band Soldiers of Jah Army, also known as SOJA. Jah also appears in The Lonely Island's "Ras Trent" as well as being the subject of "Mount Zion" by the MC Young Zeus. Jah also appears in Massive Attack's song "A Prayer for England": "Jah forgive us for forgetting, Oh Jah help us to be forgiving". Jah is also mentioned in the lyrics in "Prayer in C". Also of note is the 1991 release by American ska-punk band Sublime, titled "Jah Won't Pay the Bills". Another song which "Jah" appears in was written by the Israeli band Hatikva 6 called "If I'll Meet God", the first line of the chorus states "Eem be'yom min ha'yamim, Efgosh et Elohim, Et Allah, Jah Jah, God, Dieu, Melech hamlachim" which roughly translates to "If one day I'll meet god, Allah, Jah Jah, God, Dieu, King of Kings" which are all names of god.
"Jah" sometimes appears in other Christian music genres as well. P.O.D. recorded the song "Without Jah, Nothing," and the first line of Camper Van Beethoven's song "Take the Skinheads Bowling" is "Every day, I get up and pray to Jah". Major Lazer released a song in 2012 called "Jah No Partial".