"Jehovah" is a name for God that is found in the American Standard Version (1901) of the Old Testament. The word is actually a hybrid term, composed of four Hebrew consonants, YHWH, and vowel sounds taken from the name "Lord" (Adonai). The term "Jehovah" attempts to approximate the original term, but Yahweh is probably a closer guess, the original having been lost due to Jewish superstition against pronouncing the sacred name.
YHWH is found more than 6,800 times in the Old Testament (LORD -- all caps in most translations). It is the special name which the Lord gave to distinguish himself from the gods of the heathen world (Ex. 3:13-15). It expressed a special covenant relationship between God and Israel.
The name generally is believed to be associated with a verb that means "to be," thus suggesting the idea of a self-existing being, one with unoriginated existence (cf. Ex. 3:14). The fact that Jesus identified himself with this expression (Jn. 8:58), and that the prophets heralded the coming of Jehovah (Isa. 40:3), is clear testimony to the deity of Christ.