A point at which there is a sudden break of slope in the long profile of a river. In areas of uniform geology, the presence of a knick point may be evidence of rejuvenation; the river is forming a new, lower profile cutting first from the mouth of the river and working upstream as headward erosion takes place. See Crosby and Whipple (2006) Geomorph. 82, 1–2 and Schlunegger and Schneider (2005) Geomorph. 69, 1–4.

A knickzone is a steep reach caused by more resistant lithology, by an increase in shear stress downstream of a confluence, or by surface uplift (Bishop et al. (2005) ESPL 30, 6).

Knickzones form in response to base level fall, which is ultimately driven by eustasy, drainage capture, and tectonics (Pederson and Tressler (2012), Earth & Plan. Sci. Letts. 345–48, 171). Abbhül et al. (2011) ESPL 36, 1464 analyse distinct knickzones in river profiles on the Western Escarpment of the Andes.