The mirror of triple-top. Three tests of support that hold, followed by a break upward through the pattern's ceiling.
In practice a triple bottom is usually just a trading-range with a flat floor, and its label depends entirely on how it resolves. Treating it as a rectangle-pattern and trading the resolution is more honest than predicting the outcome from the shape.
The base-building version, where each rally off the low goes a little higher while the lows stay level, is generally considered more constructive than three identical bounces, because it shows buyers willing to pay up sooner each time.
Related: triple-top, double-bottom, support, rectangle-pattern, accumulation