Name of God, one that was revealed to us.

Ex 6:3 And I appeared unto Abraham, unto Isaac, and unto Jacob, by the name of God Almighty, but by my name Jehovah YHWH was Inot known to them.

There is a blessing for knowing his name

Psalm 91:14 Because he hath set his love upon me, therefore will I deliver him: I will set him on high, because he hath known my name.

This name has been changed in translations for various reasons and it would take a lot to explain. Some reasoning can be found here.
What is important for us is that we can call Him by name :)