A breakaway gap appears at the edge of a base or range, not in the middle of a trend. The defining features are location, at a boundary, and volume, typically far above average.
Because they mark repricing rather than noise, breakaway gaps are the class least likely to produce a quick gap-fill. Traders who use gap classification treat these as gaps to trade with, not against.
The classification is retrospective. In the moment a large gap out of a base looks identical to an exhaustion-gap at the end of a move; only the following days reveal which it was. Trading it means accepting a wide stop or waiting for the opening-range to define one.
Related: runaway-gap, exhaustion-gap, common-gap, gap-and-go, kicker-pattern