What does an invitation to an open house for a grad school mean?

[natruim]

I am starting to hear back from my grad schools and some have invited me to an open house, explicitly stating that I have not yet been admitted.

Does anyone have any experience with what exactly an invitation to an open house means? Specifically, I am interested in Berkeley nuclear engineering if anyone has experience with that as well.

Thanks!

 

[HallsofIvy]

Essentially, it is a visit to the campus at which you get to see the campus and the professors, and they get to see you! The fact that it is referred to as an "open house" implies that this is one day on which a number of people are being invited.