This is four Hebrew letters (Yod, He, Waw and He) called the "Tetragrammaton". The four characters are the four Hebrew letters that correspond to YHWH and are transliterated IAUE or Yahweh. Yahweh is the name of the Almighty Father in Heaven that people commonly call "The LORD" or "God". The reason we see "LORD" and "God" in our bibles is because of a Jewish tradition that the name Yahweh was not to be spoken for fear that the name be blasphemed. However, the scriptures declare that His name should be exalted (e.g. Ps 68:4) and the third commandment forbids this practice. The Preface of some bibles will admit why they change His name. Nearly all will cite tradition and familiarity as the reason. This, I believe is wrong. Sometimes people pronounce the tetragrammaton as "Jehovah". But Jehovah could never be the right pronunciation. On this web site, the name of Yahweh is used in reference to the Heavenly Father because in the scriptures we are told to praise, exalt, bless, love, teach, preach, anoint, assemble, believe, give thanks, honor and call on His name.
The Tetragrammaton has been found in the 2000 year old Dead Sea Scrolls and in ancient copies of the Septuagint!