The meaning of the name is unknown. Arguments favoring particular meanings have been for the most part grammatical. The name has long been thought to be a form of the verb hāwāy, an older form of the Hebrew verb hāyāh, "to be." The reconstructed form yahwēh is parsed as either a third-person Qal imperfect of this verb or as the corresponding form of the causative stem. This analysis is encouraged by theological notions of God as one who is, or who exists, or who causes existence. Thus the explanation of Yahweh in Exod 3:14, "I am who I am," is a folk etymology based on this verb (ROTT, 181–82). The analysis of the name as a causative falters on the grammatical point observed by Barr that "the causative of this verb does not occur in Hebrew elsewhere" (HDB, 335). However, the name could be a unique or singular use of the causative stem.
Anchor Bible Dictionary, Volume 6, entry for "Yahweh," section B.