Is Block Chains Used by Large Corporations?

Are large corporations using block chains? And are people in the retail space, or are they currently in a block chain? How that o this work? What is the what is this block chain you keep speaking of? Yes, it's h tha, same thing. I don't understand it's i essentially any any group that needs to be able to have those secure transactions. That's reallywha, what it's all about.