Imbalance
A gap in trading that the market often returns to fill.
An imbalance, also called a fair value gap, is a part of the chart price moved through so fast that orders were left unfilled. On candles it shows up as a gap between the wick of one candle and the wick of the candle after next. These zones matter because price frequently comes back to them: the unfilled interest is still there. An imbalance is not a signal by itself — it is a place to expect a reaction.