Jah
The name Jah means “the everlasting”.
Easton's Bible Dictionary 1897
A contraction for Jehovah (Ps. 68:4).
Smith's Bible Dictionary 1863
(Jehovah), the abbreviated form of Jehovah, used only in poetry. It occurs frequently in the Hebrew, but with a single exception, (Psalms 68:4) is rendered "Lord" in the Authorized Version. The identity of Jah and Jehovah is strongly marked in two passages of Isaiah-- (Isaiah 12:2; 26:4) [Jehovah].
International Standard Bible Encyclopedia 1915
ja.
See GOD, NAMES OF.