Knoll

A knoll is a small, isolated, rounded elevation on the seafloor, lower than a seamount, with IHO undersea-feature usage placing it below the roughly 1,000 m relief that defines a seamount. It rises smoothly from the surrounding seabed and stands alone rather than as part of a ridge. Most knolls are small volcanic edifices or eroded remnants on ridge flanks and abyssal terrain. The term is one rung of the standardized seafloor-relief ladder, abyssal hill, knoll, then seamount, used by the GEBCO Sub-Committee on Undersea Feature Names so that charted features carry consistent morphometric meaning.