In this context, ‘A’ is an instance of Type, and ‘Type’ is the type of types (usually the term used for type of type is Kind). So while ‘x’ could be the value 7

In this context, ‘A’ is an instance of Type, and ‘Type’ is the type of types (usually the term used for type of type is Kind). So while ‘x’ could be the value 7 and ‘A’ could be the type Int, the ‘B(x):Type’ means that the value of B(x) is some Type, could be Int, Char, Bool, etc.