Thanks for enlightening me.

Nothing. There are two classes in Kindergarten. One is called K and one is KX. They do that for every grade: 1, 1X 1Y. It just distinguishes the classes but has no inherent meaning. Both Kindergarten classes are AMAZING. The two teams of teachers are really strong and do terrific things. You cannot go wrong with either class. It's a great year at the school.

What does it mean?