Gap

A price range between two candles where no trading took place; it forms over the weekend, between close and open, or after news.

Opening gaps are common in stocks and indices, and a "gap fill" (the gap closing) is a frequently observed behavior, but not every gap fills. In forex, weekend gaps can trigger stop orders at a bad price.

A gap is one of the rare situations where a stop-loss doesn't protect you; reducing or closing positions before news manages this risk.