The name of a writ formerly issuing from the English chan-cery, commanding the sheriff to make ln-quiry “to what damage” a specified act. If done, will tend. Ad quod damnum is a writ which ought to be sued before the king grants certain liberties, as a fair, market, or such like, which may be prejudicial to others, and thereby it should be inquired
Source: Black's Law Dictionary 2nd Ed (1910)