In this context, ADT probably means algebraic data type: https://en.wikipedia.org/wiki/Algebraic_data_type https://en.wikipedia.org/wiki/Algebraic_data_type. An

In this context, ADT probably means algebraic data type: https://en.wikipedia.org/wiki/Algebraic_data_type https://en.wikipedia.org/wiki/Algebraic_data_type. And I don't think your definition for abstract data type is right either: usually the language feature that automatically determines types from context is called type inference.