What Is Baccalaureate?

Going to Baccalaureate?
Going to Baccalaureate?
Going to Baccalaureate?
What is Baccalaureate? Rik had never heard of Baccalaureate, and I really didn't know how to explain it to him -- which is funny, since one of my sons graduated last year and I attended a Baccalaureate, and now I have another child graduating in a couple days.