Meaning of A-D in English
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.
Campbell R. Harvey. Hypertextual finance English glossary. Английский словарь гипертекстовых финансов. 2012