Stress riser
A location where the cross-sectional area of the part changes abruptly. Stresses concentrate at such a location and failure is likely. A scratch, gouge, or tool mark in the surface of a highly stressed part can change the area enough to concentrate the stresses and become a stress riser.
Aviation Maintenance Technician Handbook — Airframe, p. G-34
Taught in AF-K Concepts, AF-K Hands-on.