a Latin preposition, originally signifying to, and frequently used in composition both with and without the d, to express the relation of one thing to another.

AD Bestias, in antiquity, is the punishment of criminals condemned to be thrown to wild beasts.

AD Hominem, in Logic, a kind of argument drawn from the principles or prejudices of those with whom we argue.

AD Ludos, in antiquity, a sentence upon criminals among the Romans, whereby they were condemned to entertain the people by fighting either with wild beasts or with one another, and thus executing justice upon themselves.

AD Metalla, in antiquity, the punishment of such criminals as were condemned to the mines, among the Romans; and therefore called Metallici.

AD Valorem, a term chiefly used in speaking of the duties or customs paid for certain goods: The duties on some articles are paid by the number, weight, measure, tale, &c.; and others are paid ad valorem, that is, according to their value.