The difference between the previous day close and the next day open if the price is significant either way then a gap forms and based on the direction we can call is bullish or bearish and based on the location where it occurs in a trading range if can be classified into 4 different gaps and in candlestick patterns analysis when previous day closing is 100 and next day the open price is 115 so the difference between the previous day closing and today’s opening is called gap.