Gap

What Does Gap Mean?
A break between prices on a chart that occurs when the price of a stock makes a sharp move up or down with no trading occurring in between. Gaps can be created by factors such as regular buying or selling pressure, earnings announcements, a change in an analyst's outlook or any other type of news release. 

Investopedia explains Gap
An example of two different gaps can be seen in the chart above. Notice how the stock closes the trading session before the first gap at $50 and opens the next trading day near $46 with no trading occurring between the two prices. Gaps are a regular occurrence in all financial markets. However, they are rarely seen in the forex market since it is highly liquid and trades 24 hours a day.