A breakout is the moment a chart''s rails change. Price has been respecting a level — either as resistance (a ceiling) or as support (a floor) — and then closes decisively through it. The previously meaningful boundary loses its meaning, and price has, at least temporarily, more room to travel.
What counts as "decisive" matters. The conventional rule: the close, not the wick, must be cleanly through the level. A wick above resistance that closes back inside the range is not a breakout; it''s a sweep that can become a false breakout if buyers don''t follow through. A full-bodied candle that closes well beyond the level — ideally with elevated volume on instruments that have meaningful volume data — is what gives a breakout its conviction.
The quality of the level being broken drives the quality of the breakout. Breaking a resistance that held three previous tests is significant; breaking one that was tested once and then ignored is almost noise. Strong breakouts come from strong levels.
The most useful post-breakout behaviour to watch for is the retest: price returns to the broken level, and the level now acts in reverse — broken resistance becomes support, broken support becomes resistance. A clean retest with rejection gives a second-chance entry with tighter risk than the breakout itself: invalidation is just back through the level.
Breakouts fail often. The two failure modes worth recognising: the false breakout (price closes through the level briefly, then reverses sharply), and the slow drift back (price closes through, ranges quietly, and slowly leaks back inside). Both are usually resolved by honouring a tight invalidation: a close back through the broken level the wrong way is the exit signal. The defence against false breakouts is the same as the entry: trade the close, honour the close.