[Question] Naming convention for "Class" model

Well, i'm having a hard time to define class name for model "Class". In PHP we can't define like this:

class Class {
    //function
}

As i learned that model naming is singular nouns.
Does anyone have any good suggestions for this case?
Thank you very much.

Comments

[Krzysztof Buczynski]

I would consider using Classes which is a plural of Class

[EqualMa]

I would use Clazz or specific phrases, for example, SchoolClass, ElementClass.