A straight line (trendline) that is drawn downward to the right across a chart along successive successive peaks. In other words, this line is drawn above the declining market peaks, i.e., over the successively lower rally highs. A tentative down trendline would need two points to be drawn, whereas a third point is needed to confirm its validity.

The opposite of a down trendline is an up trendline.

For a graphic depiction, see: down trendline- figure.