Trendline
A straight line drawn through successive swing highs (downtrend) or swing lows (uptrend) to visualise the trend's slope.
A trendline connects at least two significant swing points in the same direction and projects the slope of the trend forward. Valid trendlines require a minimum of two anchor points; a third touch confirms it.
An ascending trendline acts as dynamic support in an uptrend; a descending trendline acts as dynamic resistance in a downtrend. Breaks of well-tested trendlines are watched as potential reversal signals — but need confirmation from volume and candle structure, not just a close below the line.
On the desk
QQQ makes swing lows at $430, $437, and $445 over eight weeks. A trendline connecting $430 and $437 extends to $445 — the third touch holds, confirming the ascending trendline. Traders buy near the line with stops just below it.