AD MENTEM (iuxa mentem, iuxa modum). — This is one of the formulas commonly used in the routine responses given by the dicasteries of the Roman Curia, particularly by the Sacred Congregations, and it has the effect of adding to the rescript some condition or modality that delimits, defines, or even modifies its meaning if it is too absolute or generic, or of prescribing conditions or modalities for its execution. Such an interpretation, which is generally declared with the words “Mens est...,” is not always made public but is communicated only to the persons involved in the matter under consideration.
Enciclopedia Cattolica