A double top is a reversal pattern consisting of two price peaks: the market rallies to a new high, retraces, then rallies again to the approximate price level of the first peak and retraces again. The implication is that by failing to penetrate the first peak, the market is hitting resistance and the up trend (especially if it has been an extended one) could reverse. A double top usually looks like the letter “M”.
A double top is the opposite of a double bottom.