An abrupt change in slope. A point on a stream profile where a change in gradient occurs. This could be caused by a change in underlying bedrock or bedrock structure.
A point of significant or abrupt change stream gradient, often attributed to headward erosion related to baselevel change or tectonic uplift
a point of abrupt change or inflection in the longitudinal profile of a stream or of its valley. It is usually a waterfall or a set of rapids.