AD and Ad may refer to:Anno Domini, Latin for "In the Year of (Our) Lord", applied to years in the Julian and Gregorian calendars following 1 BCAdvertisement, the promotion of an item, service, company, and/or idea
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Advance-Decline, or measurement of the number of issues trading above their previous closing prices less the number trading below their previous closing prices over a particular period. As a technical measure of market breadth, the steepness of the A-D line indicates whether a strong bull or bear market is under way.