What is the defininitin of notch?

A notch is a small cut, groove, or indentation made in an object or surface, often to facilitate a specific function or to improve grip. In various contexts, it can refer to a notch in a scoring system, indicating a level of achievement or a mark made to denote progress. In anatomy, it can describe a small hollow or depression in a bone or organ. The term is also used in engineering and design to refer to features that enhance interlocking or alignment.