Higher High
A peak that exceeds the prior swing high — one half of the structural definition of an uptrend.
A higher high occurs when price rallies past the most recent significant peak. Combined with higher lows, a sequence of higher highs defines an uptrend in Dow Theory terms. It is the simplest structural evidence that buyers are in control and gaining ground.
A failure to make a new higher high — price stalls below the prior peak — is an early warning that the uptrend may be weakening, especially if accompanied by declining volume or bearish momentum divergence.