A breakout occurs when price pushes through a level that had previously contained it, such as the top of a range, a resistance line, or a chart pattern boundary. It signals that the prior balance between buyers and sellers at that level has shifted.
Breakouts are often examined alongside volume and follow-through, since a move that clears a level on strong participation is described differently from one that barely edges past on thin activity. A move that reverses back inside the prior boundary is sometimes called a false breakout or fakeout.
The concept describes a transition in market behavior rather than a promise of continuation. Levels can break and hold, break and reverse, or be retested, so a breakout is an observation about price crossing a reference, not an assurance of what follows.