Translation: "For further consideration"
Ad referendum literally translates as "for referring" and is a diplomatic term: Diplomats who accept a proposal for their governments ad referendum indicate by their actions that final acceptance is dependent on the approval of the diplomats' governments.

The legal phrase ad referendum is also used for assessing damages relating to privately owned land that is taken for public use.

This writ of ad referendum is of ancient origin, and could have been issued as a writ of right when a landowner was dissatisfied with the assessment of damages to his property as a result of a condemnation commission.