What is a "tetragrammatron"?

Hi,

I ordered a shirt from ebay that had a drawing of Mary and Jesus on it. It arrived today and I love that image, but on the back is a red circle with labelled parts in some other language. The invoice that came with it says "MJ Tetragrammatron tee". Is that image a "tetragrammatron"? If so, what does it mean? I've attended church most of my life and never seen that symbol anyplace else.

The Tetragrammaton is the original 4 letters used by the Hebrews that mean Yahweh. Yod, He, Wah, and He. Yahweh is what the Hebrews called God. Yahweh is still used today, but it isn't as common as using the name God.

God bless

(Yeah, but wouldn't it have been cool if it were the Megatron's brother? )