Ad.

[Cf. W. at, to, toward, Goth., O. Sax., Icel., Dan., and Eng. at, Sw. åt, Dan. ad, A-S. æt, O. H. Ger. az.] A Latin preposition, signifying to.

In composition, the last letter is usually changed into the first letter of the word to which it is prefixed. Thus for adclamo, the Romans wrote acclamo; for adgredior, aggredior; for adfirmo, affirmo; for adlego, allego; for adpono, appono; for adripio, arripio; for adscribo, ascribo; for addineo, attineo. The reason of this change is found in the ease of pronunciation, and agreeableness of the sounds.

Ad damnum. [Lat., to the damage.] (Law.) The conclusion of the declaration of a writ, in which the plaintiff states the amount of damage he claims to have been done him; sometimes used for the amount of damages claimed in a writ.—Ad filum aquæ, or ad medium filum aquæ. [Lat.] A phrase of frequent occurrence in modern law, meaning to the thread of the water; to the central one, or middle of the stream.—Ad hominem. [Lat., to the man.] (Logic.) An argument that is based on the principles of the person addressed.—Ad inquirendum. [Lat., for inquiring.] (Law.) A judicial writ commanding inquiry to be made.—Ad valorem. [Lat., according to the value.] (Com.) A term used to denote a duty or charge laid upon goods, at a certain rate per cent. upon their value, as stated in their invoice; in opposition to a specific sum upon a given quantity or number.