Field help (GACDIE) 

This field is used to enter or select any analytical dimension type parametrized in the database.
By default, if the account is subject of a screen defined in the chart of account, the loaded dimension types' codes come from the associated chart of accounts' setup. This list can be modified. If a dimension type is declared on this list, it means that the account is tracked on this dimension type.
On the contrary, if a dimension type is not declared on this list, it means that the account won't allocate it.