1530, Tyndale's transliteration of Hebrew Tetragrammaton YHWH using vowel points of Adhonai "my lord" (see Yahweh). Used for YHWH (the full name being too sacred for utterance) in four places in the Old Testament in the KJV where the usual translation the lord would have been inconvenient; taken as the principal and personal name of God.
The vowel substitution was originally made by the Masoretes as a direction to substitute Adhonai for "the ineffable name." European students of Hebrew took this literally, which yielded Latin JeHoVa (first attested in writings of Galatinus, confessor to Leo X, 1516). Jehovah's Witnesses "member of Watchtower Bible and Tract Society" first attested 1933; the organization founded c. 1879 by Charles Taze Russell (1852-1916); the name from Isaiah xliii.10.