An Inside Bar is characterized by the inside candle’s
price action being completely
covered from price action the day/period/bar before. The chart below illustrates a textbook Inside Bar.
Source (with edits):
https://www.dailyfx.com/forex/education/trading_tips/chart_of_the_day/2012/02/22/Inside_Bars_and_How_to_trade_them.html
See also:
Outside Bar
